Heterocyclic metallocenes and polymerization catalysts

ABSTRACT

A new class of heterocyclic metallocenes, a catalytic system containing them and a process for polymerizing addition polymerizable monomers using said catalytic system are disclosed; the heterocyclic metallocenes correspond to the formula (I): Y j R″ i Z jj MeQ k P l  wherein Y is a coordinating group containing a six π electron central radical directly coordinating Me, to which are associated one or more radicals containing at least one non-carbon atom selected from B, N, O, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te; R″ is a divalent bridge between the Y and Z groups; Z is a coordinating group, optionally being equal to Y; Me is a transition metal; Q is halogen or hydrocarbon substituents; P is a counterion; i is 0 or 1; j is 1–3; jj is 0–2; k is 1–3; and l is 0–2.

FIELD OF THE INVENTION

The present invention relates to new heterocyclic metallocenes and tocatalytic systems for the production of homopolymers and copolymershaving a wide range of properties, including linear low density, highdensity, atactic, isotactic and syndiotactic polymers.

More particularly, this invention relates to a new class of metallocenescontaining at least one heteroatom in a ring system associated with asix π electron central radical directly coordinating a transition metal,said metallocene being capable of polymerizing addition polymerizablemonomers.

BACKGROUND OF THE INVENTION

Polymerization of vinyl monomers, both mono-olefins and conjugateddienes, has focused on transition metal catalysts since the work ofZiegler and Natta. These catalysts are based on a central transitionmetal ion or atom surrounded by a set of coordinating ligands andmodified by various cocatalysts.

By controlling the nature of the ligand system, the central transitionmetal ion or atom, and the co-catalyst, highly active catalytic agentscan be made. In addition, catalysts can be made that yield polymers withhigh degrees of addition regularity, and in the case of non-ethylenetype monomers, stereoregular or tactioselective and/or tactiospecificpolymers can be made.

U.S. Pat. No. 3,051,690 discloses a process of polymerizing olefins tocontrolled high molecular weight polymers by the controlled addition ofhydrogen to a polymerization system that includes a hydrocarboninsoluble reaction product of a Group IVB, VB, VIB and VIII compound andan alkali metal, alkaline earth metal, zinc, earth metal or rare earthmetal organometallic compound. It is further known that certainmetallocenes, such as bis(cyclopentadienyl) titanium or zirconiumdialkyls, in combination with aluminum alkyl/water cocatalysts, formhomogeneous catalyst systems for the polymerization of ethylene.

German Patent Application 2,608,863 discloses the use of a catalystsystem for the polymerization of ethylene, consisting ofbis(cyclopentadienyl) titanium dialkyl, aluminum trialkyl and water.Furthermore, German Patent Application 2,608,933 discloses an ethylenepolymerization catalyst system including a catalyst of general formula(Cp)_(n)ZrY_(4−n), where n is a number from 1 to 4 and Y is ahydrocarbon group or a metalloalkyl in combination with an aluminumtrialkyl cocatalyst and water (Cp indicates cyclopentadienyl).

European Patent Appl. No. 0035242 discloses a process for preparingethylene and atactic propylene polymers in the presence of ahalogen-free Ziegler catalyst system of general formula(Cp)_(n)MeY_(4−n), where n is an integer from 1 to 4, Me is a transitionmetal, especially zirconium, and Y is either hydrogen, a C₁–C₅ alkyl, ametalloalkyl group or other radical, in combination with an alumoxane.

U.S. Pat. No. 5,324,800 discloses a catalyst system for polymerizingolefins including a metallocene catalyst of general formula(C₅R′_(m))_(p)R″_(s)(C₅R′_(m))MeQ_(3−p) or R″_(s)(C₅R′_(m))₂MeQ′, where(C₅R′_(m)) is a substituted Cp group, and an alumoxane.

Polyolefins can be prepared in a variety of configurations thatcorrespond to the manner in which each new monomer unit is added to agrowing polyolefin chain. For non-ethylene-polyolefins four basicconfigurations are commonly recognized, i.e. atactic, hemi-isotactic,isotactic and syndiotactic.

A given polymer may incorporate regions of each configurational type,not exhibiting the pure or nearly pure configuration.

On the opposite polymers of monomers symmetrically equivalent toethylene (i.e., the 1,1 substituents are identical and the 2,2substituents are identical, sometimes referred to as “ethylene-likemonomers”) can have no tacticity.

Atactic polymers exhibit no regular order of repeat unit orientation inthe polymer chain, i.e. the substituents are not regularly orderedrelative to a hypothetical plane containing the polymer backbone (theplane is oriented such that the substituents on the pseudo-asymmetriccarbon atoms are either above or below the plane). Instead, atacticpolymers exhibit a random distribution of substituent orientations.

Additionally, other type of catalyst belonging to the family ofmetallocene catalyst are the so-called “constrained geometry catalysts”,where one of the cyclopentadienyl groups has been replaced by aheteroatom ligand, such as an amino or phosphino anion. Such catalystsare described in U.S. Pat. Nos.: 5,453,410, 5,399,635, and 5,350,723.

Besides metallocene catalyst that produce polyethylene and atacticpolyolefins, certain metallocenes are also known to produce polymerswith varying degrees of stereoregularity or tactiospecificity, such asisotactic, syndiotactic, and hemi-isotactic polymers, which have uniqueand regularly repeating stereochemistries or substituent orientationsrelative to the plane containing the polymer backbone.

Isotactic polymers have the substituents attached to the asymmetriccarbon atoms oriented on the same side, relative to the polymerbackbone, i.e. the substituents are all either configured above or belowthe plane containing the polymer backbone. Isotacticity can bedetermined through the use of NMR. In conventional-NMR nomenclature, anisotactic pentad is represented by “mmmm” where each “m” represents a“meso” dyad or successive monomer units having the substituents orientedon the same side relative to the polymer backbone. As is well known inthe art, any inversion of a pseudo-asymmetric carbon in the chain lowersthe degree of isotacticity and crystallinity of the polymer.

In contrast, the syndiotactic structure is typically described as havingthe substituents attached to the asymmetric carbon atoms, disposedpseudo-enantiomorphically, i.e., the substituents are orientedalternately and regularly above and below the plane containing thepolymer chain. Syndiotacticity can also be determined through the use ofNMR. In NMR nomenclature, a syndiotactic pentad is represented by“rrrr”, wherein each “r” represents a “racemic” dyad, i.e. successivesubstituents on alternate sides of the plane. The percentage of “r”dyads in the chain determines the degree of syndiotacticity of thepolymer.

There are other variations in polymer structures as well. For instance,hemi-isotactic polymers are ones in which every other pseudo-asymmetriccarbon atom has its substituent oriented on the same side relative tothe plane containing the polymer backbone. While, the otherpseudo-asymmetric carbon atoms can have their substituents orientedrandomly, either above or below the plane. Since only every otherpseudo-asymmetric carbon is in an isotactic configuration, the term hemiis applied.

Isotactic and syndiotactic polymers are crystalline polymers and areinsoluble in cold xylene. Crystallinity distinguishes both syndiotacticand isotactic polymers from hemi-isotactic and atactic polymers, thatare soluble in cold xylene and are non-crystalline. While it is possiblefor a catalyst to produce all four types of polymers (atactic,hemi-isotactic, isotactic and syndiotactic), it is desirable for acatalyst to produce predominantly or essentially isotactic orsyndiotactic polymers having very little atactic contents and fewstereochemical defects.

Several catalysts that produce isotactic polyolefins are disclosed inU.S. Pat. Nos. 4,794,096 and 4,975,403, as well as European Pat. Appl.0,537,130. Several catalysts that produce syndiotactic polyolefins aredisclosed in U.S. Pat. Nos. 3,258,455, 3,305,538; 3,364,190, 4,852,851,5,155,080, 5,225,500, and 5,459,117.

Besides neutral metallocenes, cationic metallocenes are known to resultin polymers with varying degrees of tactiospecificity. Cationicmetallocene catalysts are disclosed in European Patent Applications277,003 and 277,004. Catalysts that produce hemi-isotactic polyolefinsare disclosed in U.S. Pat. No. 5,036,034.

In addition to homopolymers of monoolefins, polymerization catalysts forpreparing copolymers of monoolefins, or polymers of di-functionalolefins, or copolymers of di-functional olefins and monoolefins can beprepared using coordinated metal catalysts, including metallocenecatalysts.

Although many metallocene catalysts are now available, the need for newligand systems and new metallocene catalysts or catalyst precursors forthe polymerization of olefins is still important and would represent asignificant advancement in the art. Such new ligand systems and thecatalysts derived therefrom can offer new design approaches for makinghighly-stereoregular or tactiospecific polymers essentially free ofdefects, polymers with controlled defect statistics, and copolymers withcontrolled properties, or new approaches for molecular weight controland for the control of other polymer properties.

SUMMARY OF THE INVENTION

The present invention provides a new class of heterocyclic metallocenesfor the polymerization of olefins useful to prepare polymer productswith desired properties, such as a given molecular weight, molecularweight distribution, density, tacticity and/or terminal unsaturation.

The metallocenes according to the present invention contain at least oneheteroatom in a ring system associated with a six π electron centralradical directly coordinating a transition metal belonging to Group 3,4, 5, 6 or to the lanthanide or actinide series of the Periodic Table ofthe Elements (IUPAC version).

Said metallocenes are useful for the polymerization of additionpolymerizable monomers, such as α-olefins, into homopolymers and/orcopolymers.

The metallocenes of the present invention comprise organometalliccoordination compounds of mono, di or tri-functional ligand systemscoordinated to transition metal complexes, preferably complexes of anelement of Group 3, 4, or 5 or of the lanthanide series of elements fromthe Periodic Table, where the ligand system includes at least one six πelectron central radical to which are associated one or more radicalscontaining at least one heteroatom.

The metallocenes of the present invention correspond to formula (I):Y_(j)R″_(i)Z_(jj)MeQ_(k)P_(l)  (I)wherein

-   (1) Y is a coordinating group containing a six π electron central    radical directly coordinating Me, to which are associated one or    more radicals containing at least one non-carbon atom selected from    B, N, O, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te;-   (2) R″ is a divalent bridge between the Y and Z groups;-   (3) Z is a coordinating group having the same meanings as Y or is an    open pentadienyl containing group, a cyclopentadienyl containing    group, a heterocyclic cyclopentadienyl containing group, a nitrogen    containing group, a phosphorous containing group, an oxygen    containing group or a sulfur containing group;-   (4) Me is an element belonging to Group 3, 4, 5, 6 or to the    lanthanide or actinide series of the Periodic Table of Elements;-   (5) Q is a linear or branched, saturated or unsaturated alkyl    radical, aryl radical, alkylaryl radical, arylalkyl radical or a    halogen atom;-   (6) P is a stable non-coordinating or pseudo non-coordinating    counterion;-   (7) i is an integer having a value of 0 or 1;-   (8) j is an integer having a value from 1 to 3;-   (9) jj is an integer having a value from 0 to 2;-   (10) k is an integer having a value from 1 to 3; and-   (11) l is an integer having a value from 0 to 2.

Moreover, formula (I) also describes cationic metallocenes where l=1 or2. Said cationic metallocenes can be prepared by reacting an ion-pair ora strong Lewis acid compound with a neutral metallocene (i.e., 1=0) toform a cationic metallocene, either prior to or concurrent withcontacting the neutral metallocene with monomer. Cationic metallocenesare used analogously to neutral ones to polymerize addictionpolymerizable monomers.

Another object of the present invention is a class of ligands of formula(II):Y_(j)R″_(i)Z_(jj)  (II)wherein Y, R″, Z, j, i and jj have the meanings reported above; saidligands are useful as intermediates in the preparation of theheterocyclic metallocenes of the present invention.

Another object of the present invention is a catalytic system for thepolymerization of addition polymerisable monomers, comprising thereaction product between:

-   an heterocyclic metallocene of formula (I) and-   a suitable co-catalyst.

The present invention further provides a process for polymerizingaddition polymerizable monomers comprising contacting at least one ofthe above catalytic systems with at least one addition polymerizablemonomer. Preferably, the metallocene and the monomer are contactedtogether in a reaction zone. Alternatively, the metallocenes of formula(I) can be combined with a co-catalyst, such as an alkyl aluminum or analumoxane, either prior to or after the metallocene of formula (I) isbrought into contact with monomer.

Furthermore, the metallocenes of formula (I) may be used forpre-polymerization before polymerisation with bulk monomer and/or priorto the stabilization of the reaction conditions.

The present invention can also be practiced to produce intimate blendsof different types of polymers by contacting a metallocene of formula(I) designed for each different polymer type with one or more monomers.

The preferred applications of practicing this invention is in theproduction of polyethylene, polyethylene copolymers, isotactic,syndiotactic, hemi-isotactic or atactic polypropylene, or mixturesthereof, polypropylene copolymers, as well as polymers and copolymers ofother addition polymerizable monomers.

The present invention further includes methods for preparingmetallocenes of formula (I) and their ligands, and methods foractivating the metallocenes of formula (I) where 1=0 into catalyticallyactive polymerization agents.

DETAILED DESCRIPTION OF THE INVENTION

In the present detailed description the following definitions are used:

-   “Central Radical” means a six π electron radical directly    coordinating the transition metal, such as the five member bring in    cyclopentadiene, indene or fluorene;-   “HCy” means a ligand including a central six π electron radical    having an associated radical containing at least one heteroatom;-   “Cp” means a cyclopentadienyl ring;-   “HCp” means a Cp ring containing one or more heteroatoms;-   “Op” means an open pentadienyl ligand having five atoms in an all    cis configuration and having six π electrons delocalized over the    five atoms;-   The “h-” prefix will be used to connote the heterocyclic analogs of    aromatic ring systems containing a central five membered ring and a    heterocyclic fused ring, e.g. h-Ind for an indene or indane ring    system containing at least one heteroatom in the six membered ring    of the fused ring system, h-Flu for a fluorene or fluorane ring    system containing at least one heteroatom in one or both of the six    membered rings of the fused ring system, or h-Pta for a pentalene or    pentalane ring system containing a least one heteroatom in only one    of the fused five membered rings of the pentalene ring system; and-   “o-” prefix will be used to connote the open-pentadienyl analog of    above described fused ring systems

The Applicant found a new class of heterocyclic metallocenes with wideapplication for the production of polymers of addition polymerizablemonomers; said metallocenes present two to three coordinating ligands,where at least one of said coordinating ligands has a central six πelectron radical directly coordinated to a suitable transition metal, towhich is associated a group containing at least one heteroatom(sometimes abbreviated “HCy” group). The electrons in the HCy group canbe delocalized over the entire groups.

The present invention is directed towards metallocenes and catalyticsystems containing them useful in the polymerization of additionpolymerizable monomers. In particular, the present invention is directedtowards metallocenes and catalytic systems for the polymerization ofpolymerizable vinyl monomers, including α-olefins (such as ethylene,propylene and butylene) to produce polymers such as linear low densitypolyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene(isotactic, syndiotactic, hemi-isotactic, atactic or mixtures thereof).The resulting polymers are intended for fabrication into articles byextrusion, injection molding, thermoforming, rotational molding, orother techniques known in the state of the art.

The polymers which can be prepared using the metallocenes of thisinvention include homopolymers and copolymers of vinyl monomers, havingfrom 2 to 20 carbon atoms, and preferably from 2 to 12 carbon atoms;said vinyl monomers are preferably ethylene, propylene, butylene andstyrene. In addition, said vinyl monomers can also include variousheteroatoms, such as acrylonitrile and vinyl pyridine.

The heterocyclic metallocenes of this invention contain one or moremono-, bi- and/or tri-functional ligands coordinated to, complexed with,or otherwise associated with a suitable transition metal, where at leastone of said ligands is a HCy ligand coordinating the transition metal.

Particularly preferred heterocyclic metallocenes of the presentinvention include those represented by formula (I):Y_(j)R″_(i)Z_(jj)MeQ_(k)P_(l)  (I)where:

-   (1) Y is a coordinating ligand comprising a six π electron central    radical, directly coordinating Me, to which is associated a group    containing at least one non-carbon atom selected from B, N, O, Al,    Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te;-   (2) R″ is a divalent bridge linking Y and Z and can be a linear or    branched C₁–C₂₀ alkenyl radical, a C₃–C₁₂ bicyclic radical, an aryl    radical or a diaryl allyl radical, said radicals optionally    containing silicon, germanium, phosphorous, nitrogen, boron or    aluminum atoms;-   (3)Z is a coordinating group having the same meanings as Y or is an    open pentadienyl containing group, a cyclopentadienyl containing    group, a heterocyclic cyclopentadienyl containing group, a nitrogen    containing group, a phosphorous containing group, an oxygen    containing group or a sulfur containing group;-   (4) Me is an element belonging to Group 3, 4, or 5 or to the    lanthanide series, preferably Lu, La, Nd, Sm, or Gd;-   (5) Q is a linear or branched, saturated or unsaturated alkyl    radical, aryl radical, alkylaryl radical, arylalkyl radical or a    halogen atom;-   (6) P is a stable non-coordinating or pseudo non-coordinating    counterion;-   (7) i is an integer having a value of 0 or 1;-   (8) j is an integer having a value from 1 to 3;-   (9) jj is an integer having a value from 0 to 2;-   (10) k is an integer having a value from 1 to 3; and-   (11) l is an integer having a value from 0 to 2.

A particularly important subclass of the metallocenes of this inventionare represented by formula (III):YR″ZMeQ_(k)P_(l)  (III)where Y is a HCy group and Z is a non-HCy group and where R″, Me, Q, P,k, and l are as described above (i=1, j=1 and jj=1 in formula (I)) andYR″Z is a ligand of the invention.

Non limiting examples of said metallocenes are:

-   isopropylidene(cyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-methylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-methylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-ethylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-ethylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-i-propylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-i-propylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-n-butylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-n-butylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(3-trimethylsilylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   dimethylsilanediyl(3-trimethylsilylcyclopentadienyl)(7-cyclopentadithiophene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   isopropylidene(3-methylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   dimethylsilanediyl(3-methylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   isopropylidene(3-ethylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   dimethylsilanediyl(3-ethylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   isopropylidene(3-i-propylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   dimethylsilanediyl(3-i-propylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylcyclopentadienyl)(7-cyclopentadipyrrole)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   isopropylidene(3-methylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   dimethylsilanediyl(3-methylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   isopropylidene(3-ethylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   dimethylsilanediyl(3-ethylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   isopropylidene(3-i-propylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   dimethylsilanediyl(3-i-propylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylcyclopentadienyl)(7-cyclopentadiphosphole)zirconium    dichloride;-   isopropylidene(2-methylthiapentalene)(2-methylindene)zirconiumdichloride;-   dimethylsilanediyl(2-methylthiapentalene)(2-methylindene)zirconiumdichloride;-   isopropylidene(2-ethylthiapentalene)(2-ethylindene)zirconiumdichloride;-   dimethylsilanediyl(2-ethylthiapentalene)(2-ethylindene)zirconiumdichloride;-   isopropylidene(2-i-propylthiapentalene)(2-i-propylindene)zirconiumdichloride;-   dimethylsilanediyl(2-i-propylthiapentalene)(2-i-propylindene)zirconiumdichloride;-   isopropylidene(2-t-butylthiapentalene)(2-t-butylindene)zirconiumdichloride;-   dimethylsilanediyl(2-t-butylthiapentalene)(2-t-butylindene)zirconiumdichloride;-   isopropylidene(2-trimethylsilylthiapentalene)(2-trimethylsilylindene)zirconium    dichloride;-   dimethylsilanediyl(2-trimethylsilylthiapentalene)(2-trimethylsilylindene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(thiapentalene)zirconium dichloride;-   dimethylsilanediyl(cyclopentadienyl)(thiapentalene)zirconium    dichloride;-   isopropylidene(indenyl)(thiapentalene)zirconium dichloride;-   dimethylsilanediyl(indenyl)(thiapentalene)zirconium dichloride;-   isopropylidene(fluorenyl)(thiapentalene)zirconium dichloride;-   dimethylsilanediyl(fluorenyl)(thiapentalene)zirconium dichloride;-   isopropylidene(cyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   phenylmethylsilanediyl(cyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-ethylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-ethylthiapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-n-butylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-n-buthylthiapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-i-propylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-i-propylthiapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-phenylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-phenylthiapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-naphthylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)    (2-naphthylthiapentalene)zirconium dichloride;-   isopropylidene(cyclopentadienyl)(2-trimethylsilylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-trimethylsilylthiapentalene)zirconium    dichloride;-   1,2-ethandiylbis(cyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-methylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-methylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-ethylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-ethylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-i-propylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-i-propylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-n-butylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-n-butylylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylylcyclopentadienyl)(2-methylthiapentalene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopenta[1.2]thiophene[1.4]cyclopentadiene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylylcyclopentadienyl)(7-cyclopenta[1.2]thiophene[1.4]cyclopentadiene)zirconium    dichloride;-   dimethylstanyl(3-t-butylylcyclopentadienyl)(7-cyclopenta[1.2]thiophene[1.4]cyclopentadiene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopenta[1.2]thiophene[1.4]cyclopentadiene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylylcyclopentadienyl)(7-cyclopenta[1.2]thiophene[1.4]cyclopentadiene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(azapentalene)zirconium dichloride;-   dimethylsilanediyl(cyclopentadienyl)(azapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-methyltazapentalenyl)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   phenylmethylsilanediyl(cyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-ethylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-ethylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-n-butylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-n-buthylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-i-propylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-i-propylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-phenylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-phenylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-naphthylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-naphthylazapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(2-trimethylsilylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(2-trimethylsilylazapentalene)zirconium    dichloride;-   1,2-ethandiylbis(cyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-methylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-methylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-ethylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-ethylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-i-propylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-i-propylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-n-butylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-n-butylylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylylcyclopentadienyl)(2-methylazapentalene)zirconium    dichloride;-   isopropylidene(3-t-butylcyclopentadienyl)(7-cyclopenta[1.2]pyrrole[1.4]cyclopentadiene)zirconium    dichloride;-   dimethylsilanediyl(3-t-butylylcyclopentadienyl)(7-cyclopenta[1.2]pyrrole[1.4]cyclopentadiene)zirconium    dichloride;-   dimethylstanyl(3-t-butylylcyclopentadienyl)(7-cyclopenta[1.2]pyrrole[1.4]cyclopentadiene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(oxapentalene)zirconium dichloride;-   dimethylsilanediyl(cyclopentadienyl)(oxapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(borapentalene) zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(borapentalene)zirconium    dichloride;-   isopropylidene(cyclopentadienyl)(phosphapentalene) zirconium    dichloride;-   dimethylsilanediyl(cyclopentadienyl)(phosphapentalene)zirconium    dichloride.

Another important subclass of metallocenes according to the presentinvention are represented by the formula (IV):YR″YMeQ_(k)P_(l)  (IV)wherein the Y groups, same or different from each other, are HCy andwhere R″, Me, Q, P, k, and l are as described above (i=1, j=2 and jj=0in formula (I)) and YR″Y is a ligand of the invention.

Non limiting examples of these metallocenes are:

-   isopropylidene(2-methylthiapentalene)zirconiumdichloride;-   dimethylsilandiylbis(2-methylthiapentalene)zirconiumdichloride;-   isopropylidene(2-ethylthiapentalene) zirconiumdichloride;-   dimethylsilandiylbis(2-ethylthiapentalene) zirconiumdichloride;-   isopropylidene(2-i-propylthiapentalene) zirconiumdichloride;-   dimethylsilandiylbis(2-i-propylthiapentalene) zirconiumdichloride;-   isopropylidene(2-t-butylthiapentalene) zirconiumdichloride;-   dimethylsilandiylbis(2-t-butylthiapentalene) zirconiumdichloride;-   isopropylidene(2-trimethylsilylthiapentalene) zirconiumdichloride;-   dimethylsilandiylbis(2-trimethylsilylthiapentalene)    zirconiumdichloride;-   isopropylidene(2-i-phenylthiapentalene) zirconiumdichloride;-   dimethylsilandiylbis(2-i-phenylthiapentalene) zirconiumdichloride;-   isopropylidenebis(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-diethyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-diethyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-t-butyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-t-butyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-n-butyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-n-butyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-trimethylsilyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-trimethylsilyl-1-azapentalene-4-yl)zirconium    dichloride;-   diphenylsilandiylbis(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   methylphenylsilandiylbis(1-phenyl-2,5-di-methyl-1-azapentalene-4-yl)zirconium    dichloride;-   ethylphenylsilandiylbis(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   1,2-ethandiylbis(1-phenyl-2,5-di-methyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-diethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-diethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-t-butyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-t-butyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-n-butyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-n-butyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(1-phenyl-2,5-di-trimethylsilyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiylbis(1-phenyl-2,5-di-trimethylsilyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   diphenylsilandiylbis(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   methylphenylsilandiylbis(1-phenyl-2,5-di-methyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   ethylphenylsilandiylbis(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   1,2-ethandiylbis(1-phenyl-2,5-di-methyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-dimethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-dimethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-diethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-diethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-di-n-butyl-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-di-n-butyl-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-di-1-propyl-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-di-1-propyl-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-di-(3-pyridyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-di-(3-pyridyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2-methyl-6-(3-pyridyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2-methyl-6-(3-pyridyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2-methyl-6-(3-chinolyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2-methyl-6-(3-chinolyl)-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidenebis(4-phenyl-2,6-di-trimethylsilyl-1-thiopentalene-3-yl)zirconium    dichloride;-   dimethylsilandiylbis(4-phenyl-2,6-di-trimethylsilyl-1-thiopentalene-3-yl)zirconium    dichloride;-   1,2-ethandiylbis(4-phenyl-2,6-dimethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   1,3-propandiylbis(4-phenyl-2,6-dimethyl-1-thiopentalene-3-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-methyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-methyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-t-butyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-t-butyl-2,5-dimethyl-1-azapentalene-4-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-methyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-methyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-t-butyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-t-butyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   isopropylidene(3-methylthiopentalene-4-yl)(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;-   dimethylsilandiyl(3-methylthiopentalene-4-yl)(1-phenyl-2,5-dimethyl-1-phosphapentalene-4-yl)zirconium    dichloride;

Another subclass of metallocenes of the invention is represented byformulae (III) or (IV), wherein i=0 and the remaining variable have themeanings reported above.

Non limiting examples of these metallocenes are:

-   bis(2-methylthiapentalene)zirconiumdichloride;-   bis(2-methylazapentalene)zirconiumdichloride;-   bis(2-methylphosphapentalene)zirconiumdichloride;-   bis(2-ethylthiapentalene)zirconiumdichloride;-   bis(2-ethylazapentalene)zirconiumdichloride;-   bis(2-ethylphosphapentalene)zirconiumdichloride;-   bis(2-i-propylthiapentalene)zirconiumdichloride;-   bis(2-i-propylazapentalene)zirconiumdichloride;-   bis(2-i-propylphosphapentalene)zirconiumdichloride;-   bis(2-t-butylthiapentalene)zirconiumdichloride;-   bis(2-t-butylazapentalene)zirconiumdichloride;-   bis(2-t-butylphosphapentalene)zirconiumdichloride.

As used in the description of the metallocenes of formulae (I), (III)and (IV), the term “associated” to a central atom, in the context of thegroup containing at least one heteroatom, “associated to a central 6 πelectron radical, means that said heteroatom is not an endocyclic memberof the central six electron radical directly coordinating Me. Forexample, the heteroatom could be part of a ring condensed to the centralsix electron radical, such as in thiapentalene, azapentalene,dithiatricyclounnonatetraene, diazatricyclounnonatetraene or inthiaazatricyclounnonatetraene or the heteroatom can be part of a radicallinked to the central six electron radical, such as a heterocyclicradical substituent bonded to the central radical (e.g. 3-pyridylCpgroup).

Yet, another important subclass of metallocenes of this invention arethose capable of producing polymers having varying degrees of tacticity.Such metallocenes are generally represented by bridged metallocenes offormulae (III) and/or (IV) (i.e., containing bridged ligands) havingspecific substitution patterns that are capable of impartingtactioselectivity to the metallocenes during polymerization, resultingin the formation of tactioselective polymers.

Generally, tactioselective catalysts, and even tactiospecific catalysts,are formed when in the metallocenes of formulae (III) and (IV), Y and/orZ groups bear the same or different substituents, in some or all of thepositions α and β to the atoms bearing the bridging group R″, such thatat least one β substituent is a bulky substituent (i.e. stericallybulkier than hydrogen and preferably sterically bulkier than a methylgroup or an aromatic carbon atom, which has essentially the samerelative steric size as a methyl group). Preferably, said metallocenespossess a specific overall symmetry. Additional information on theeffect of bulky β substituent can be found in U.S. Pat. No. 5,459,117.

Metallocenes of formulae (III), capable of yielding polymers withvarying degrees of selectivity to the isotactic joining of monomer units(“isoselective metallocenes”), including nearly isospecific polymers(“isospecific metallocenes”), must show either C2 or pseudo-C2 symmetry.In isoselective metallocenes neither Y nor Z is bilaterally orpseudo-bilaterally symmetric, and both Y and Z have a single bulky βsubstituent irrespective of the number and type of α-substituents.Alternatively, in isoselective metallocenes Y or Z, but not both, isbilaterally or pseudo-bilaterally symmetric and the non-bilaterallysymmetric group has only one bulky β substituent. Analogous isoselectivemetallocenes can be designed from the metallocenes of formula (IV), butwhere the substituents are on one or both of the Y ligands.

Metallocenes of formula (III) capable of yielding polymers with varyingdegrees of selectivity to the syndiotactic joining of monomer units(“syndioselective”), including syndiospecific polymers (“syndiospecificmetallocenes”), must show either Cs or pseudo-Cs symmetry. Insyndioselective catalysts both Y and Z are bilaterally orpseudo-bilaterally symmetric and either Y or Z, but not both, have bulkyβ substituents irrespective of the number and type of α-substituents.Analogous syndioselective metallocenes can be designed from themetallocenes of formula (IV), but all substitution will occur on the twoY groups.

In the case of metallocenes of formulae (III) and (IV) having non Cptype groups (i.e. ligands not having six π electrons delocalized overfive atoms either in an all cis configuration or in a five memberedring, such as NR⁻, PR⁻, O⁻ or S⁻), the substituents on the non-Cp typegroup and the substituents on the HCy group must operate to stericallyconstrain the metallocenes so that the resulting polymer has some degreeof tacticity. In the case of oxide or sulfide containing metalloceneswhere the oxygen or sulfur atom is bridged through the divalent bridgeR″ to the HCy ligand, the HCy ligand will impose the control overpolymer chain propagation by the existence of one or more substituents.

In a particularly preferred class of metallocenes of the presentinvention, the Y ligand is a heterocyclic ring fused to the central sixπ electron central radical. Said class is envisaged by formulae (I),(III) and (IV), wherein Y is a substituted cyclopentadienyl grouprepresented by the following structure:

wherein the groups R^(a), identical or different from each other, areselected from the group consisting of hydrogen, linear or branched,saturated or unsaturated C₁–C₂₀-alkyl, C₃–C₂₀-cycloalkyl, C₆–C₂₀-aryl,C₇–C₂₀-alkylaryl and C₇–C₂₀-arylalkyl radicals, and wherein at least twoadjacent R^(a) groups can form a condensed heterocyclic C₅–C₇ ringcontaining at least one non-carbon atom selected from B, N, O, Al, Si,P, S, Ga, Ge, As, Se, In, Sn, Sb and Te;

-   R^(b) is hydrogen, halogen, linear or branched, saturated or    unsaturated, C₁–C₂₀-alkyl, C₁–C₂₀-alkoxyl, C₆–C₂₀-aryl,    C₇–C₂₀-alkylaryl, C₇–C₂₀-arylalkyl C₁–C₂₀ acyloxyl group, optionally    containing a silicon atom, or R^(b) is a bridging divalent group R″    as defined above.

The preferred Y groups are represented by the following formulae:

wherein:

-   (i) the X atoms, the same or different from each other, can be N, P,    NR^(g), PR^(g), 0 or S; when a fused ring has two heteroatoms, then    one X can be 0 or S and the other X can be N, P, NR^(g) or PR^(g),    or one can be N or P and the other can be NR^(g) or PR^(g), so that    the molecular species represents a chemically viable group;-   (i) wherein R^(g) is a linear or branched C₁–C₂₀ hydrocarbon    radical, optionally substituted with one or more halogen, hydroxy,    alkoxy group, a C₃–C₁₂ cyclohydrocarbon radical, a C₃–C₁₂    cyclohydrohalocarbon radical, optionally substituted with one or    more halogen, C₆–C₂₀ aryl radical, C₇–C₂₀ alkylaryl radical, C₇–C₂₀    arylalkyl radical, a silicon hydrocarbon radical, a germanium    hydrocarbon radical, a phosphorous hydrocarbon radical, a nitrogen    hydrocarbon radical, a boron hydrocarbon radical, an aluminum    hydrocarbon radical or a halogen atom;-   (ii) the R groups, same or different from each other, can be    hydrogen, a linear or branched C₁–C₂₀ hydrocarbon radical,    optionally substituted with one or more halogen, hydroxy, alkoxy, a    C₃–C₁₂ cyclohydrohalocarbon radical, optionally substituted with one    or more halogen, an C₆–C₂₀ aryl radical, an C₇–C₂₀ alkylaryl    radical, an C₇–C₂₀ arylalkyl radical, a silicon hydrocarbon radical,    a germanium hydrocarbon radical, a phosphorous hydrocarbon radical,    a nitrogen hydrocarbon radical, a boron hydrocarbon radical, an    aluminum hydrocarbon radical or a halogen atom, two adjacent R    groups can form together a saturated, unsaturated, or aromatic fused    ring;-   (iii) n and m are integers which have values from 0 to the maximum    number of substituents that the ring can accommodate (e.g. for    formulae (a)–(b), n can be 0, 1 or 2); and-   (iv) R^(α) and R^(β) representing α and β substituents respectively,    same or different from each other, can be hydrogen, a linear or    branched C₁–C₂₀ hydrocarbon radical, optionally substituted with one    or more halogen, hydroxy or alkoxy, a C₃–C₁₂ cyclohydrocarbon    radical, optionally substituted with one or more halogens, an C₆–C₂₀    aryl radical, an C₇–C₂₀ alkylaryl radical, an C₇–C₂₀ arylalkyl    radical, a silicon hydrocarbon radical, a germanium hydrocarbon    radical, a phosphorous hydrocarbon radical, a nitrogen hydrocarbon    radical, a boron hydrocarbon radical, an aluminum hydrocarbon    radical or a halogen atom; two adjacent R^(α) and R^(β) groups can    form together a saturated, unsaturated, or aromatic fused ring;-   (v) R^(a) and R^(b) have the meanings reported above.

In its broadest form, the process of the present invention involvespolymerizing an addition polymerizable monomer, such as an α-olefin,either alone or together with other addition polymerizable monomers, inthe presence of the catalytic system of the invention, including atleast one metallocene of formula (I) and a co-catalyst, such as analumoxane.

The present invention further provides a process for producingtactioselective and even tactiospecific polymers comprising contactingat least one polymerizable monomer with a catalytic system of theinvention including at least one metallocene of formulae (III) and/or(IV), where the ligands of said metallocenes bear tacticity controllingα and β substituents, as described herein.

Many metallocenes of formulae (I), (III) and (IV) that are capable ofproducing tactioselective and/or tactiospecific polymers when contactedwith monomers capable of forming polymers with tacticity, have certainspecific substitution requirements, often imparting then actual orpseudo symmetry. The symmetry terms generally used to describemetallocenes that generate tactioselective polymers are described below.

The term bilateral symmetry means that the ligand, such as the HCygroup, Op group or Cp group is symmetric with respect to a bisectingmirror plane perpendicular to the plane containing the legend, andbisecting the ligand into two parts with the 2 and 5 and the 3 and 4positions being in a mirror image relationship respectively (e.g.3,4-dimethyl-Cp or 2,5-dimethyl-Cp). The term pseudobilateral symmetrymeans that the 3,4 and 2,5 substituents are of similar but not identicalsteric bulk. (e.g. methyl and ethyl, phenyl and pyridyl, naphthyl andquinoline, methyl and chloro, hydrogen and fluoro, etc).

The term C_(s) or pseudo-C_(s) symmetry means that the entiremetallocene is symmetric with respect to a bisecting mirror planepassing through the bridging group and the atoms bonded to the bridginggroup, i.e. the substituents on each coordinating group of a bridgedlegend, which are reflectively coupled, are identical or similar. C_(s)or pseudo-C_(s) symmetry also means that both coordinating groups arebilaterally or pseudo bilaterally symmetric. Syndioselectivemetallocenes show C_(s) or pseudo-C_(s) symmetry and preferably includetwo coordinating groups linked together by a divalent bridge (i=1 andj+jj=2 in formula (I)) and the β substituents on one coordinating groupare sterically larger than the β substituents on the other coordinatinggroup. For example, (dithia-tricyclo[3.3.1.0.0]unnonatetraenyl)-R″-(Cp)ligands, (dithiatricyclo[3.3.1.0.0]unnonatetraenyl)-R″-(Op) ligands,(dithia-tricyclo[3.3.1.0.0]unnonatetracnyl)R″-(3,4-di-t-butyl Cp)ligand, or (dithia-tricyclo[3.3.1.0.0]unnonatetraenyl)R″(2,5-dimethyl-Cp) ligands have C_(s) symmetry or pseudo C_(s) symmetrydepending on the location of the two sulfur atoms.

(Dithia-tricyclo[3.3.1.0.0]unnonatetraenyl)-R″-(2-chloro-5-methyl-Cp),ligands(dithia-tricyclo[3.3.1.0.0]unnonatetraenyl)-R″-(3-tbutyl-4-isopropyl-Cp)-ligandsor related ligands have pseudo-C_(s) symmetry. Forming appropriatemetallocenes from these ligands will produce catalytic systems capableof yielding polymers with varying degrees of syndiotacticity includingpolymers with very high degrees of syndiospecificity.

The term C₂ or pseudo-C₂ symmetry means that the ligand has an axis ofC₂ symmetry passing through the bridging group and, if the ligand systemwere confided to a plane, the axis would be perpendicular to the planecontaining the ligand. Isoselective metallocenes have generally C₂ orpseudo-C₂ symmetry and preferably include two coordinating groups linkedtogether by a divalent group (i=1 and j+jj=2 in formula (I)), where atleast one β substituent on one coordinating group is bulkier than the βsubstituent in the same location on the other coordinating group andwhere only the racemic metallocenes are active isoselective species. Forexample, rac-bis(N-phenyl-5-methyl-1-azapentalenyl)R″ ligands,rac-bis(5-methyl-1-thiapentalenyl)R″ ligands andbis(cyclopenta[b]quinoline) R″ ligands have C₂ symmetry.

Rac-(N-phenyl-5-methyl-1-azapentalenyl)-R″-(3-phenyl-indenyl) ligandsand rac(4-phenyl-1-thiapentalenyl)-R″-(3-phenyl-indenyl) have pseudo-C₂symmetry. To produce isoselective metallocenes, the ligands arecontacted with an appropriate metallic species which yields a mixture ofmeso isomers (which yield atactic polymer) and rac isomers (which yieldisoselective polymers). The meso and rac isomers can be separated bycrystallization or other separation techniques, well known in the art.The synthesis of cyclopenta[b]quinolines is described in Eisch, J. J.;Gadek, F. J, J. Org. Chem., 1971, 36, 2065–2071.

Moreover, isoselective metallocenes can also be prepared that do nothave inactive meso forms. Such isoselective metallocenes generallycomprise one bilaterally symmetric coordinating group and one asymmetriccoordinating group (not bilaterally or pseudo-bilaterally symmetric).

In accordance with this invention, one can also produce olefincopolymers particularly copolymers of ethylene and/or propylene, andother olefins by a suitable choice of metallocenes of formula (I). Thechoice of metallocenes of the present invention can be used to controlcomonomer content, as well as other properties of the polymer, such astacticity for vinyl monomers other than ethylene or ethylene likemonomers.

As already reported above, the metallocenes of the present inventioncomprise one or more rings containing at least one heteroatom,associated with the central six π electron radical which directlycoordinates the transition metal. Such associated rings include thefollowing classes of radicals:

-   (i) the heteroatom(s) is contained in a cyclic substituent linked to    one of the atoms of the central radical;-   (ii) the heteroatom(s) is contained in a ring fused to the central    radical, but is not an endocyclic member of the central radical; or-   (iii) the heteroatoms are contained in both a cyclic substituent    linked to the central radical and in a ring fused to the central    radical. The rings fused to the central radical can be aromatic,    non-aromatic, unsaturated and/or unsaturated ring or ring systems.    Additionally, the central radical can include the    phosphino-boratabenzene radicals (that are prepared according to the    procedure described in Quan, R. W. et al, J. Am. Chem. Soc., 1994,    116, 4489).

Examples of heterocyclic ring systems that can be associated with thecentral radical include, without limitation, any B, N, O, Al, Si, P, S,Ga, Ge, As, Se, In, Sn, Sb or Te, containing group, any group containingtwo or more of these atoms and preferably any N, O, P, or S containinggroup or any group containing two or more of these preferred atoms. Notlimitative examples include pyrrole, isopyrroles, pyrazole,isoimidazole, 1,2,3-triazole, 1,2,4-triazole, imidazole, indolizine,thiophene, 1,3-dithiole, 1,2,3-oxathiole, 1,2-dithiole, thiazole,isothiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,3,4-oxadiazole,1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole, thionaphthene,isothionaphthene, isoindazole, benzoxazole, anthranil, benzothiophene,naphthothiophene, furane, isobenzofuran, benzofuran, indole, indazole,purine, carbazole, carboline, isothiazole, isoxazole, oxazole, furazan,thienofuran, pyrazinocarbazole, furopyran, pyrazolo-oxazole,selenazolo-benzothiazole, imidazothiazole, furocinnoline,pyridocarbazole, oxathiolopyrole, imidazotriazine,pyridoimidazo-quinoxaline, sila-2,4-cyclopentadiene, thiapentalenes,azapentalenes and dithiatricyclounnonatetraenes.

Additional HCy radicals include, without limitation, heterocyclic fusedring systems where the heteroatom is not a part of the central Cp ringssuch as compounds represented by formulae (a) and (s) shown above. Notlimitative examples include mono heteroatom containing fluorenes wherethe heteroatom is in the 1–8 positions (using IUPAC numbering);diheteroatom fluorenes again where the heteroatoms are in the 1–8positions, mono heteroatom indene where the heteroatom is in the 4–7positions (IUPAC numbering); diheteroatom indenes again where theheteroatom is in the 4–7 positions. Heterocyclic compounds includingthia and aza pentalene type systems or heterocyclic compounds includingthia, dithia, aza, diaza and thiaaza systems, having three fused fivemember rings, where the central five membered ring is an all-carboncyclopentadienyl ring.

Of course, it should be apparent that certain of these ring systems willnot support substituents at the heteroatom. Thus, oxygen and sulfurcontaining rings will not have substituents attached to the oxygen orsulfur atoms. Additionally, in the case of N, P, and As, where theseatoms are part of a double bond, they will not have substituentsattached thereto.

The term open-pentadienyl (abbreviated as Op) is intended to refer toall six π electron structures that are centered on five connected atomsin an all cis configuration, but where the five atoms bearing the six πelectrons are not part of a five membered ring, i.e., the five atoms donot form a cyclopentadienyl ring system. Of course, all five atomsshould be sp² hybridized or in some other hybridization that can supportelectron delocalization over the five centers. One possible precursor tothe Op ligands of this invention is a system where four of the atoms arepart of two non-conjugated double bonds connected to and separated by acentral atom, where the double bonds contribute two electrons each tothe ligand system and the central atom supplies two electrons to thesystem either directly (as the ion pair of a N or P atom) or through theloss of a removable group, to result in the formation of an anioniccenter as for a C or Si atom. Of course, other central species could beused as well, including Ge and As.

The open-pentadienyl radical suitable for use in the present inventioninclude Op ligands of formula (V):

wherein:

-   G is a carbon atom, a nitrogen atom, a silicon atom or a phosphorus    atom;-   L is a CR³R^(3′) radical, a SiR³R^(3′) radical, a NR^(3″) radical, a    PR^(3″) radical, an oxygen atom or a sulfur atom and L′ is a    CR⁴R^(4′) radical, a SiR⁴R^(4′) radical, a NR^(4″) radical, a    PR^(4″) radical, an oxygen atom or a sulfur atom; R², R³, R^(3′),    R^(3″), R⁴, R^(4′), R^(4″) and R⁵, the same or different from each    other, can be a hydrogen, a linear or branched C₁–C₂₀ hydrocarbon    radical, a linear or branched C₁–C₂₀ halocarbon radical, a linear or    branched C₁–C₂₀ hydrohalocarbon radical, a linear or branched C₁–C₂₀    alkoxy radical, a C₃–C₁₂ cyclohydrocarbon radical, a C₃–C₁₂    cyclohydrohalocarbon radical, a C₆–C₂₀ aryl radical, a C₇–C₂₀    alkylaryl radical, a C₇–C₂₀ arylalkyl radical, a silicon hydrocarbon    radical, a germanium hydrocarbon radical, a phosphorous hydrocarbon    radical, a nitrogen hydrocarbon radical, a boron hydrocarbon    radical, an aluminum hydrocarbon radical or a halogen atom; R² and    R³, R^(3′) or R^(3″) and/or R⁵ and R⁴, R^(4′) or R^(4″) can form a 4    to 6 membered ring or a 6 to 20 fused ring systems; R³, R^(3′), or    R^(3″) and R⁴, R^(4′), or R^(4″) can be joined together so that the    five numbered atomic centers forming the five centered delocalized    six electron ligand are contained in a 7 to 20 membered ring system.

The numbers associated with the five atoms in formula (V) are there toindicate how substituent positions will be addressed in the remainder ofthe specification. Thus, for those metallocenes having a divalentbridge, said bridge will be bonded to the central atom which isindicated as position 1, in a fashion analogous to the numbering incyclopentadiene. Additionally, the 2 and 5 positions will sometimes bejointly referred to as the α positions or proximal positions (proximalto the 1 position), while the 3 and 4 positions will sometimes bejointly referred to as the β or distal positions.

The present invention also provides a process for producing polymers andcopolymers having varying and controllable properties including highmolecular weights at high temperatures, tactioselectivity (includingtactiospecificity), stereoregularity, narrow or broad molecular weightdistribution, etc. The process comprises polymerizing one or moremonomers in the presence of one or more metallocenes of the invention.

The Applicant has found that metallocenes of the present invention canalso be prepared which yield stereoregular and stereospecific polymerproducts, such as linear high molecular weight polyethylene, isotacticpolyolefins, syndiotactic polyolefins and hemi-isotactic polyolefins.These uniquely designed metallocenes have as a key feature a bridgedspecifically substituted legend, containing at least one HCycoordinating group.

For metallocenes that produce stereoselective and/or tactioselectivepolyolefins, the ligand that forms the metallocene of the presentinvention can be substituted in such a way that the same metallocene isstereorigid (bridged), stereolocked and stereodirected so that: (1) thesubstituents on the legend lock and/or direct the polymer chain-endorientation and/or monomer approach such that each successive monomeraddition is stereospecific and the degree of stereoselectivity can becontrolled; and (2) the bridging group renders the ligand system rigidso that its rotation or isomerization is prevented or restricted. Thesemetallocenes are characterized by having β or distal substituents on theligands controlling the orientation of monomer addition; moreover,metallocene configuration determines tactioselectivity.

The metallocenes of the present invention can be eithernon-stereorigid/non-stereolocked, stereorigid/non-stereolocked,non-stereorigid/stereolocked, stereorigid/stereolocked or mixturesthereof. Stereorigidity is imparted to the metallocenes of thisinvention by a chemical bridge connecting two coordinating groups toform metallocenes of formulae (III) and (IV), i.e. where i=1 and j=1 inthe general formula (I). The bridging group prevents or greatlyrestricts the two coordinating groups from undergoing structuralisomerizations or rotation.

The Applicant has also found that, by controlling the metallocenesrelative steric size, catalysts can be formed that insert statisticallycontrollable defects into the resulting polymers. The Applicant has alsofound that catalysts of the present invention can be designed to producehemi-isotactic polymers. The Applicant has also found that intimatemixtures of polymers with different properties can be prepared bypolymerizing monomers in the presence of metallocenes of the presentinvention or polymerizing monomers in the presence of catalysts of thisinvention in combination with prior art catalysts.

In the state of the art, the term metallocene denotes an organometalliccoordination compound in which two cyclopentadienyl containing ligandsare coordinated to or “sandwiched” about a central metal atom and whereall five centers of the Cp ring are involved in metal coordination. Themetal atom may be a transition metal or transition metal halide,alkyhalide or alkoxide. Such structures are sometimes referred to as“molecular sandwiches” since the cyclopentadienyl ligands are orientedabove and below a plane containing the central coordinated metal atomnearly parallel to the planes containing the Cp ring. Similarly, theterm “cationic metallocene” means a metallocene in which the centralcoordinated metallic species carries appositive charge, i.e., themetallocene complex is a cation associated with a stablenon-coordinating or pseudo non-coordinating anion.

However, in addition to the traditional meaning of the term metallocene,the present invention expands this term to encompass metallocenes whereat least one of the groups coordinating the central metal atom or ion isa ring system containing at least on heteroatom, associated with thecentral radical (the central radical directly coordinates the transitionmetal). The second coordinating group can be a ring system having themeanings of the first coordinating group or a heterocyclic containinggroup where the heteroatom is in the central ring, an Op containingligand or a Cp containing ligand, a nitrogen ligand, a phosphorusligand, an oxygen ligand or a sulfur ligand.

One skilled in the art should also recognize that the permissible valuesfor i, j, k and l will depend on the actual ligand and on thecoordinating metal; these values are understood to conform to knownorganometallic structural and electronic requirements.

Suitable Z radicals for use in the present invention include, withoutlimitation, radicals represented as follows:

-   (1) heterocyclic containing ligands where the heteroatom is    contained in the central radical;-   (2) Op containing ligands;-   (3) cyclopentadienyl or substituted cyclopentadienyl radicals of    formula (C₅R′_(iii)), wherein the groups R′, same or different from    each other have the meanings of R, and two adjacent R′ groups can be    joined together to form a C₄–C₆ ring; iii is an integer having a    value from 0 to 5;-   (4) nitrogen and phosphorus containing radicals, represented by the    formula (JR⁶ _(jjj)) where J is nitrogen or phosphorus atom, the R⁶    groups, same or different from each other, have the meanings    described above for radicals R¹–R⁵; jjj is an integer having a value    from 1 to 3; or-   (5) an oxygen or sulfur containing radical represented by the    formula (UR⁷ _(kkk)), where U is oxygen or sulfur atom and where R⁷    is a radical as described above for radicals R¹–R⁵; and kkk is an    integer having a value of 0 or 2.

Suitable structural bridging groups R″ able to impart stereorigidity tothe metallocenes of this invention, include, without limitation, alinear or branched C₁–C₂₀ alkenyl radical, a C₃–C₂₀ dialkyl methylradical, a C₃–C₁₂ cyclohydrocarbon radical, an C₆–C₂₀ aryl radical, adiarylmethylene radical, a diaryl allyl radical, a silicon hydrocarbonradical, dihydrocarbon silenyl radical, a germanium hydrocarbyl radical,a phosphorous hydrocarbon radical, a nitrogen hydrocarbon radical, aboron hydrocarbon radical and an aluminum hydrocarbon radical.

Other suitable bridging groups R″ include ionic units, such as B(C₆F₅)₂and Al(C₆F₅)₂, and R₂C, R₂Si, R₄Et, R₆Pr, where R can be anyhydrocarbon, cyclic hydrocarbon, cyclic or linear hydrocarbon bearinganother organometallic catalyst or carboranes. Indeed, the bridges canbe C₂ bridges (and C₃ etc.) which form the backbone of polymericsupports (e.g. the atactic, syndiotactic and isotactic polymers fromvinyl-indene and 9-vinyl-fluorene etc.) as well as functionalizedpolystyrene precursors and all other polymers with terminal or branchedboron or Al functional groups which are bonded to the catalysts, e.g.,in zwitterionic form. R₂C and R₂Si bridging groups are preferred withisopropylidene and dimethylsilenyl bridging groups being particularlypreferred.

Suitable radicals corresponding to R, R′, R¹–R⁵, R^(α) and R^(β)include, without limitation, hydrogen atoms, linear or branched C₁–C₂₀hydrocarbon radicals, linear or branched C₁–C₂₀ halocarbyl radicals,linear or branched C₁–C₂₀ hydrohalocarbon radicals, linear or branchedC₁–C₂₀ alkoxy radicals, C₃–C₁₂ cyclohydrocarbon radicals, a C₃–C₁₂cyclohydrohalocarbon radicals, aryl radicals, allylaryl radicals,arylalkyl radicals, silicon hydrocarbon radicals, germanium hydrocarbonradicals, phosphorus hydrocarbon radicals, nitrogen hydrocarbonradicals, boron hydrocarbon radicals, aluminum hydrocarbon radicals andhalogen atoms. Preferable, said radicals are linear or branched C₁–C₂₀alkyl radicals, trialkylsilyl radicals and aryl radicals, where linearor branched C₁–C₁₀ radicals and aryl radicals are particularlypreferred; methyl, ethyl, isopropyl, trialkylmethyl radicals,trialkylsilyl radicals, and phenyl radicals are especially preferred.

Additionally, suitable radicals corresponding to R, R′, R¹–R⁵, R^(α) andR^(β) include, without limitation, zwitterionic radicals such asCp-B(C₆F₅)₃ ⁻, Cp-Al(C₆F₅)₃ ⁻, Cp-Al(CF₃)₃ ⁻, Cp-X—Al(C₆F₅)₃ ⁻ andCp-X—B(C₆F₅)₃ ⁻, where X can represent an alkenyl group or an alkenoxygroup.

The metallocenes of this invention containing zwitterionic radicals oneither one of the coordinating group the ligand of the present inventionand having Me=metal of group 4 do not need an independent and sometimesstereochemically interfering counterion (i.e., 1=0). These zwitterionicradicals may also be suitable for mono and di cations of metallocenes offormula (I) where Me is a group 5 metal in the plus five oxidation state(Me(V)). They could even conceivably be used to create ion-pairmetallocenes with the normally neutral group 3 metals in the plus threeoxidation state (Me(III)). In this case, one could obtain heterogeneousinsoluble ion-pair systems for improved polymer particle size andmorphology control.

Preferred metals corresponding to Me include, without limitation, Group3, 4, or 5 elements or lanthanide elements from the Periodic Table ofElements. More preferably, Me is a Group 4 or 5 metal, titanium,zirconium and hafnium being the most preferred. Preferred lanthanideelements are Lu, La, Nd, Sm and Gd.

Suitable hydrocarbon radicals or halogens corresponding to Q include,without limitation, a linear or branched C₁–C₂₀ alkyl radical, an arylradical, an alkylaryl radical, an arylalkyl radical, F, Cl, Br and I. Qis preferably methyl or halogen, and more preferably chlorine atom.

Exemplary hydrocarbon radicals are methyl, ethyl, propyl, butyl, amyl,isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl,2-ethylhexyl and phenyl. Exemplary alkylene radicals are methylene,ethylene, propylene and isopropylidenyl. Exemplary halogen atoms includefluorine, chlorine, bromine and iodine, chlorine being preferred.Examples of the alkylidene radicals are methylidene, ethylidene andpropylidene. Exemplary nitrogen containing radicals include amines suchas alkyl amines, aryl amines, arylalkyl amines and alkylaryl amines.

Suitable non-coordinating anions corresponding to P in the generalformula include, without limitation, [BF₄]⁻, B(PhF₅)⁻ ₄, [W(PhF₅)₆]⁻,[Mo(PhF₅)₆]⁻ (wherein PhF₅ is pentafluorophenyl), [ClO₄]⁻, [S_(n)O₆]⁻,[PF₆]⁻, [SbR₆]⁻ and [AIR₄]⁻; wherein each R is independently Cl, a C₁–C₅alkyl group (preferably a methyl group), an aryl group (e.g. a phenyl orsubstituted phenyl group) or a fluorinated aryl and alkyl group.

Tactioselective metallocenes (i.e. metallocenes that producetactioselective polymers) of the present invention are generallycharacterized by having symmetry or pseudo symmetry associated with theligand or the metallocene. As stated previously, metallocenes includingtwo ligands and having C₂ or pseudo-C₂ symmetry or having onebilaterally symmetric ligand and one asymmetric ligand and at least onebulky β-substituent or pseudo β-substituent (in the case of metalloceneshaving non-Cp groups such as constrained geometry amine or phosphineanionic ligands) produce polymers with varying degrees of isotacticity.In contrary, metallocenes including two ligands and having C_(s) orpseudo-C_(s) symmetry produce polymers with varying degrees ofsyndiotacticity. Preferably, the ligands are bridged, but certainnon-bridged two metallocenes can give polymers with varyingtactioselectivity or polymers with varying degrees of regularity in themode of monomer addition, e.g., head-to-tail or tail-to-head additionregularity.

Of the metallocenes of this invention, titanocenes, zirconocenes andhafniocenes are most preferred. The present invention also encompassesLa, Lu, Sm, Nd and Gd metallocenes.

A few exemplary metallocenes of the present invention are metalloceneswhere:

-   (1) Y, in the YR″Z ligand, corresponds to formulae (a)–(s) where    R^(β) is a bulky substituent or where the R substituent in    combination with the ring atom β to the carbon attached to R″ forms    a bulky β substituent; or-   (2) the two Y groups in the YR″Y ligand, same or different from each    other, corresponds to formulae (a)–(s), where R^(β) is a bulky    substituent or where the R substituent in combination with the ring    atom β to the carbon attached to R″ forms a bulky β substituent.

A few exemplary metallocenes of the present invention are metalloceneswhere:

-   (1) Y, in the YR″Z ligand, corresponds to formulae (a)–(s) and Z is    a Cp radical; Y and Z are bilaterally symmetric and only one of    either Y or Z has two bulky β substituents; or-   (2) the two Y groups, in the YR″Y ligand, same or different from    each other are bilaterally symmetric and correspond to formulae    (a)–(s), where only one of the Y group has two bulky β substituents.

Yet another important subclass metallocenes of this invention are thosecapable of producing partially crystalline thermoplastic-elastomericpropylene polymers, directly obtainable from the polymerization reactionof propylene without the need of separation steps or of sequentialpolymerization, which are endowed with good mechanical properties andcan be suitably used as elastomeric materials and as compatibilizers forblends of amorphous and crystalline polyolefins.

Said metallocenes are unbridged metallocenes corresponding to formula(I) wherein i=0, j=1, jj=1 (i.e. containing two unbridged ligands)having specific substitution patterns, thus obtaining polypropyleneshaving isotactic and atactic blocks within a single polymer chain, orblends of isotactic and atactic polymer chains, exhibiting elastomericproperties.

In formula (I), Y and Z, equal or different from each other, arepreferably unbridged ligands corresponding to formula (hh)′:

wherein X, R, n and m have the meanings reported above.

Said metallocenes are not rigid and upon isomerisation the catalystsymmetry alternates between a chiral and an achiral geometry; thegeometry alternation in the metallocenes of the invention can becontrolled by selecting suitable bulky unbridged ligands Y and Z, aswell as suitable polymerization conditions:

Non limiting examples of the above described metallocenes are:

-   bis(4-phenyl-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-diethyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dipropyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-i-propyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-n-butyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-t-butyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-trimethylsilyl-thiopentalene)zirconium    dichloride;-   bis(4-(2-pyridyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(3-pyridyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(8-chinolyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(3-chinolyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(5-pyrimidyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(2-furanyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(2-pyrolyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(3,5-dimethylphenyl)-2,6-dimethyl-thiopentalene)zirconium    dichloride;-   bis(4-(3,5-diethylphenyl)-2,6-dimethyl-thiopentalene)zirconium    dichloride;-   bis(4-(3,5-dimethylsilylphenyl)-2,6-dimethyl-thiopentalene)zirconium    dichloride;-   bis(4-methyl-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(trifluoromethyphenyl)-2,6-dimethyl-thiopentalene)zirconium    dichloride;-   bis(4-naphthyl-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-(1-indenyl)-2,6-dimethyl-thiopentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-diethyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dipropyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-i-propyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-n-butyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-t-butyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-trimethylsilyl-azapentalene)zirconium    dichloride;-   bis(4-(2-pyridyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(3-pyridyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(8-chinolyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(3-chinolyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(5-pyrimidyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(2-furanyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(2-pyrolyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(3,5-dimethylphenyl)-2,6-dimethyl-azapentalene)zirconium    dichloride;-   bis(4-(3,5-diethylphenyl)-2,6-dimethyl-azapentalene)zirconium    dichloride;-   bis(4-(3,5-dimethylsilylphenyl)-2,6-dimethyl-azapentalene)zirconium    dichloride;-   bis(4-methyl-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(trifluoromethyphenyl)-2,6-dimethyl-azapentalene)zirconium    dichloride;-   bis(4-naphthyl-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-(1-indenyl)-2,6-dimethyl-azapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dimethyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-diethyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dipropyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-i-propyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-n-butyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-t-butyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-di-trimethylsilylphosphapentalene)zirconium    dichloride;-   bis(4-(2-pyridyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(3-pyridyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(8-chinolyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(3-chinolyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(5-pyrimidyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(2-furanyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(2-pyrolyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(3,5-dimethylphenyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(3,5-diethylphenyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-(3,5-dimethylsilylphenyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-methyl-2,6-dimethyl-phosphapentalene)zirconium dichloride;-   bis(4-phenyl-2,6-dimethyl-phosphapentalene)zirconium dichloride;-   bis(4-(trifluoromethyphenyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride;-   bis(4-naphthyl-2,6-dimethyl-phosphapentalene)zirconium dichloride;    and-   bis(4-(1-indenyl)-2,6-dimethyl-phosphapentalene)zirconium    dichloride.

Indeed, the metallocenes can be tailored using a number of strategies tocontrol properties, such as the relative stereoselectivity and/orstereospecificities, the molecular weight, and other significant polymerproperties. Metallocenes having a single carbon bridged ligands havebeen more stereospecific than the silicon bridged analogs forsyndiotactic specific catalysts; the carbon bridged metallocenes aregenerally less stereospecific than the silicon bridged analogs forisospecific catalysts. The larger the steric requirements are for theβ-substituents, the more stereospecific the metallocene is. Thedifference in the steric requirements for the conformational locks andthe stereo-controlling β-substituent can be used to optimize theorientation of the chain end. And substituents at the α-position shouldresult in increased polymer molecular weight.

The present invention is directed to both neutral metallocenes andcationic metallocenes as evidenced by the subscript l associated withthe anion P having permissible values of 0 to 2, i.e., when l=0, themetallocenes are neutral and when l=1 or 2 the metallocenes arecationic, as evidenced by the inclusion of an anion is the generalformula.

The metallocenes of the present invention can also be designed toproduce polymers with very high tacticity indices depending on thedesired tacticity. In order to produce tactically specific polymers frommetallocenes of the present invention, the characteristics of theβ-substituents on the bridged ligands are important. Thus, the “stericrequirement” or “steric size” of the β-substituents can be designed tocontrol the steric characteristics of metallocenes, so that thearrangement of β-substituents allows control of the stereochemistry ofeach successive monomer addition.

It may also be possible to strategically arrange substituents with theproper steric properties on an appropriate carbon(s) of the metalloceneof the present invention which should serve as chain end conformationallocks (preferably positioned in the mouth of the ligand) and which couldalso confer solubility (ion pair separation for better catalyst activityand stereospecificity) and/or insolubility (for better control ofpolymer morphology), as desired. The bridged, substituted metallocenesare stereorigid, provide chain-end conformational locks, and aresuperior to those without such conformational locks.

Prior art has shown, for example, that a methyl substituent positionedat the α-Cp position on the C₅ ring of bisindenyl catalysts increasesthe molecular weight of isotactic polypropylene produced with theEt[Ind]₂ZrCI₂ based catalyst. Similarly, a methyl substituent on the C6ring of the indenyl ring system has reduced the stereospecificity;depending on the positional isomerism.

Moreover, the addition of methyl, t-Bu, OMe and Ph substituents to thecoordinating groups of the ligand and to the bridging group R″ have hadsteric, solubility and electronic influences on catalysts insyndiotactic and isotactic specific polymerizations.

By making the sterically larger β-substituents different and/or thesterically smaller β-substituents different, the tactioselectiveversions of the metallocenes of the present invention can be designed toimpart any degree of tacticity to the resulting polymers. Thus, if oneβ-substituent is t-butyl and another is ethyl, and the other two aremethyls, the tactiospecificity of the metallocenes will be reducedrelative to the one having two t-butyls and two methyls.

Of course, cationic metallocenes require the anion P to maintain theirnet neutrality. The anion P in the general formula is preferentially acompatible non-coordinating or pseudo-non-coordinating anion that eitherdoes not coordinate with the metallocene cation or only weaklycoordinates to the cation, yet remains sufficiently labile so that itcan be readily displaced by a neutral Lewis base such as a monomer unit.Compatible non-coordinating or pseudo-noncoordinating anions aredescribed as anions that stabilize the cationic metallocenes, but do nottransfer an electron or electron equivalent to the cation to produce aneutral metallocene and a neutral byproduct of the non-coordinating orpseudo-non-coordinating anion.

The useful size of the counterion P also depends on the bulkiness orsteric requirements of the ligands. In addition to size, othercharacteristics are important for good anions or counterions, such asstability and bonding. The anion must be sufficiently stable so that itcannot be rendered neutral by virtue of the metallocene cation electronextraction and the bond strength with the cation must be sufficientlyweek not interfere with monomer coordination and chain propagation.

A preferred procedure for producing cationic metallocenes of the presentinvention (l=1 or 2) involves the reaction of an ion-pair in anon-coordinating solvent with a metallocene of formula (I), where l=0.For example, triphenylcarbenium tetrakis(pentafluorophenyl)boronate or asimilar ion-pair may be reacted with a neutral metallocene of thepresent invention in a solvent such as toluene to generate thecorresponding cationic metallocene. This preparation method is wellknown in the state of the art, as described for instance in U.S. Pat.No. 5,225,550.

A preferred application of the present invention is in thepolymerization of alpha olefins, preferably ethylene and propylene, toproduce highly linear, low, medium and high density polyethylene, aswell as atactic, isotactic, syndiotactic, hemi-isotactic polypropylenesor mixtures thereof. However, the metallocenes of the invention may beused in the preparation of hemi-isotactic, isotactic or syndiotacticpolymers obtained from other ethylenically unsaturated monomers. Forexample, syndiospecific, isospecific or hemi-isospecific polymers of1-butene, 1-pentene, 1-hexene and styrene can be prepared using themetallocenes of the present invention.

Addition polymerizable monomers suitable for use in this inventioninclude ethylenically unsaturated monomers or any organic moleculehaving a terminal vinyl group (CH₂═CH), such as α-olefins (e.g.propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene), vinylhalides (e.g. vinyl fluoride and vinyl chloride), vinyl arenes (e.g.styrene, alkylated styrenes, halogenated styrenes and haloalkylatedstyrenes), dienes (e.g. 1,3-butadiene and isoprene). Polyethylene andpolypropylene are probably of the greatest practical significance andthe invention will be described in detail with reference to theproduction of polyethylenes and/or polypropylene polymers, but it shouldbe understood that this invention is generally applicable to alladdition polymerizable monomers. These catalysts may also be useful inthe polymerization of dienes to elastomers through the inclusion of1,4-addition instead of 1,2-addition. Of course, these catalysts mayalso be useful in varying the relative amounts of 1,2-addition versus1,4-addition polymers containing conjugated diene monomers.

The polymerization procedure using the metallocenes according to thepresent invention is carried out according to procedures known in theart, such as the one disclosed in U.S. Pat. No. 4,892,851.

In the catalytic systems according to the present invention themetallocenes according to the present invention are used in associationwith various co-catalysts. Although many of the species are activealone, they can be activated upon the addition of various cocatalysts.Co-catalysts, usually organo-aluminum compounds such astrialkylaluminum, trialkyloxyaluminum, dialkylaluminum halides oralkylaluminum dihalides may be used in the present invention. Especiallysuitable alkylaluminums are trimethylaluminum and triethylaluminum(TEAL), the latter being the most preferred. Methylalumoxane (MAO) isalso usable in carrying out the methods of the present invention,especially for neutral metallocenes, in amounts well in excess of thestoichiometric equivalent.

The alumoxanes are polymeric aluminum compounds which can be representedby the general formulae (R—Al—O)_(n), which is a cyclic compound, andR(R—Al—O—)_(n)—AlR₂, which is a linear compound, where R is a C₁–C₅alkyl group, such as methyl, ethyl, propyl, butyl and pentyl, and n isan integer from 1 to 20. Most preferably, R is methyl and n is 4.

Generally, in the preparation of alumoxanes from aluminum trialkyl andwater, a mixture of the linear and cyclic compounds is obtained. Thealumoxane can be prepared in various ways. Preferably, they are preparedby contacting water with a solution of aluminum trialkyl, such as, forexample, aluminum trimethyl, in a suitable organic solvent, such asbenzene or an aliphatic hydrocarbon. For example, the aluminum alkyl istreated with water in the form of a moist solvent. In an alternativemethod, the aluminum alkyl can be contacted with a hydrated salt, suchas hydrated copper sulfate. Preferably, the alumoxane is prepared in thepresence of a hydrated copper sulfate: a dilute solution of aluminumtrimethyl in toluene is treated with copper sulfate represented by thegeneral formula CuSO₄.5H₂O. The ratio of copper sulfate to aluminumtrimethyl is desirably about 1 mole of copper sulfate for 4 to 5 molesof aluminum trimethyl. The reaction is evidenced by the evolution ofmethane.

The ratio of aluminum in the alumoxane to total metal in the metallocenecan be in the range of 0.5:1 to 10,000:1, and preferably 5:1 to 1000:1.The solvents used in the preparation of the catalytic systems of theinvention are preferably inert hydrocarbons, in particular hydrocarbonsinert with respect to the metallocene.

Such solvents are well known and include, for example, isobutane,butane, pentane, hexane, heptane, octane, cyclohexane,methylcyclohexane, toluene and xylene. As a further control andrefinement of polymer molecular weight, one can vary the alumoxaneconcentration: higher concentrations of alumoxane in the catalyticsystem of the invention result in higher polymer product molecularweight.

Since, in accordance with this invention, one can produce high viscositypolymer products at relatively high temperature, temperature does notconstitute a limiting parameter as with the prior artmetallocene/alumoxane catalyst. The catalytic systems described herein,therefore, are suitable for the polymerization of olefins in solution,slurry or gas phase polymerizations and over a wide range oftemperatures and pressures. For example, such temperatures may be in therange of −60° C. to 280° C. and preferably in the range of 50° C. to160° C. The pressures employed in the process of the present inventionare those usually employed in the state of the art, preferably in therange of 1 to 500 atmospheres and greater.

In a solution phase polymerization, the alumoxane is preferablydissolved in a suitable solvent, typically an inert hydrocarbon solventsuch as toluene and xylene, in molar ratios of about 5×10⁻³ M. However,greater or lesser amounts can be used. The soluble metallocenes of theinvention can be converted to supported heterogeneous catalytic systemsby depositing said metallocenes on catalyst supports known in the art,such as silica, alumina and polyethylene. The solid catalytic systems,in combination with an alumoxane, can be usefully employed in slurry andgas phase olefin polymerizations.

After polymerization and deactivation of the catalyst, the obtainedpolymer can be recovered by processes well known in the art for removalof deactivated catalysts and solution. The solvents may be flashed offfrom the polymer solution and the polymer obtained extruded into waterand cut into pellets or other suitable comminuted shapes. Pigments,antioxidants and other additives, as is known in the art, may be addedto the polymer.

The polymer product obtained in accordance with the process of theinvention have a weight average molecular weight ranging from about 500to about 1,400,000 and preferably from about 1000 to 500,000. Themolecular weight distribution (Mw/Mn) ranges preferably from 1.5 to 4,but higher values can be obtained. The polymers contain 1.0 chain endunsaturation per molecule. Broadened MW can be obtained by employing twoor more of the metallocenes of this invention in combination with thealumoxane. The polymers produced by the process of this presentinvention are capable of being fabricated into a wide variety ofarticles, as is known for polymer products derived from additionpolymerizable monomers.

The metallocene used in the present invention may be prepared byprocedures known in the art, as disclosed in U.S. Pat. No. 4,892,851,while the active cationic metallocenes may be produced by simplyconverting the neutral metallocenes into the cationic state followingknown procedures, such as those disclosed in EP 0 277 003 and 0 277 004or by reaction with triphenylcarbenium boronates. Similarly,alcohol—B(PhF₅)₃ complexes can be used as anionic precursors forpreparing the active cationic metallocenes of the present inventionwhere the alcoholic proton reacts with an amine of an alkyl group on thecoordinating metal atoms to generate a cationic metallocene and analkoxide—B(PhF₅)₃ anion.

The metallocenes of this invention can also be converted to supportedheterogeneous catalytic systems by depositing the catalysts on supportsincluding, without limitation, silica, alumina, magnesium dichloride andpolystyrene beads. Supported metallocenes can improve the bulk densityof the polymer, as further described in U.S. Pat. Nos. 4,935,474 and4,530,914, and EP 0 427 697 and 0 426 638.

The metallocenes of the invention can also be chemically linked tosupport by placing functional groups with ion pairs or Lewis acidcenters or Lewis base centers on the ligands and/or supports. Supportingcan also be achieved by using large (oligomeric or polymeric) insolubleanions as counter ions.

The metallocene of the present invention can be used to prepare low,medium and high molecular weight polymers, low, moderate and highdensity polymers, elastomers, aspecific, isospecific, syndiospecificand/or hemi-isospecific polymers, not only of propylene, but of allα-olefins, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene andCH₂═CH(CH₂)_(p)Si(CH₃)₃ where p is 1 to 4. Additionally, themetallocenes of this invention can polymerize singly or in mixtures alladdition polymerizable monomers including vinyl monomers and dienemonomers.

One of ordinary skill should recognize that the metallocenes of theinvention, that can give rise to isoselective catalysts, can beseparated into a meso form, which is asymmetric, and a rac form that isselective to isotactic polymers. The stereospecific rac metallocenes canbe separated from the meso form by crystallization. It is well knownfrom the Bercaw et al. (J. Ann. Cherry Soc. 1992, 1 14, 7607 J. E.Bercaw and E. B. Coughlin.) that rac-metallocenes, free of theundesirable aspecific meso stereoisomers, can be prepared by placingsuitable bulky substituents, such as Si(Me)₃, on the ligand atoms in αposition to the bridgehead atom.

The metallocenes of the present invention can be used alone or inmixture with other metallocene catalysts, TiCl₃/DEAC and/orTiCl₄/MgCl₂/TEAL catalysts having internal electron donors such asdiisobutylypthalate, and external donors, such asdiphenyldimethoxysilane and methanol to produce polymers with mixedstereochemical compositions, distributions or tailored molecular weightdistributions. Reactor blends of polymers with optimized physical,thermal, mechanical and rheological properties can be tailored toproduce the optimum mixture for specific applications requiring highmelt strength, high clarity, high impact strength and high rates ofcrystallization, simply by mixing catalytic species together inappropriate ratios.

The metallocenes of the present invention influence the rate oftermination by β-hydride elimination reactions. This, therefore,provides a novel ligand effect for controlling polymer molecularweights. These metallocenes can be exploited to tailor molecular weightsand hence molecular weight distributions with mixed species of thecatalysts and any other class of catalysts. This would be advantageousin tailoring the polymer properties in HDPE, LLDPE, i-PP, s-PP, etc.Similarly the chain-end conformation locking substituent will influencethe rate of reactivity of the new metallocenes with α-olefins such aspropylene, butene and hexene. The new ligand effects on the catalystreactivity ratios can be exploited to produce reactor blends withvarying compositions, sequences, distributions and/or molecular weightdistributions. The metallocenes of the present invention provideimproved tailored grades of polypropylene and propylene-ethylene highimpact copolymers, as reactor blends or from reactors in series,including fluidized and stirred gas phase polymerizations.

The metallocenes of the present invention can also be used to producecopolymers of olefins and copolymers of olefins and dienes with varyingdegrees of tactiospecificity.

Hereinafter is described a general process for the preparation of themetallocenes of the present invention. In said process, it is importantthat the metallocene is “pure”, because low molecular weight, amorphouspolymers can be produced by impure metallocenes.

Generally, the preparation of metallocenes comprises forming andisolating the ligand (bridged or unbridged), which is then aromatized ordeprotonated to form a delocalized electron system or an hetero anion,and subsequently reacted with a metal halide or alkylide to form thefinal complex.

The synthesis procedures are generally performed under an inert gasatmosphere, using a glove box or Schlenk techniques. The synthesisprocess generally comprises the steps of 1) preparing the halogenated oralkylated metal compound, 2) preparing the ligand, 3) synthesizing thecomplex, and 4) purifying the complex.

The synthesis of the bridged ligands of the present invention having theβ-substituted Cp can be prepared by contacting a suitable substitutedfulvene with a suitable substituted cyclopentadienyl containing an anionring, under reaction conditions sufficient to produce a bridgedstructure, to yield ligands with either C₂ or C_(s) or pseudo-C₂ orpseudo C_(s) symmetry.

Fulvene is cyclopentadiene with an exo-cyclic methylene group at the 1position of cyclopentadiene ring. The exo-cyclic methylene carbon is the6 position of fulvene. Since this carbon can ultimately become thebridging group R″ in formula (I), the preferred fulvenes for thepreparation of the present metallocenes are 6,6-disubstituted fulvenesso that the resulting bridging group is a tertiary carbon atom.

The fulvenes useful in preparing the ligands of the present inventionhave substituents in the 3 and 4 positions Q and are generally 6,6disubstituted, while the other sites can be substituted or unsubstitutedas shown below:

where R′p is the substituent on the resulting Cp ring and where the T,T′ and the exocyclic carbon (C6 in fulvene) are the precursors of thestructural bridging group R″.

As noted previously, a preferred method of converting the neutralmetallocenes to cationic metallocenes useful in the present inventioninvolves reaction of the neutral metallocenes with a triphenylcarbeniumboronate. A preferred reactant is triphenylcarbeniumtetrakis(pentafluorophenyl)boronate.

The catalysts of the present invention can also be used to preparepre-polymerized catalysts according to methods known in the art, such asthe one disclosed in U.S. Pat. Nos. 3,893,989, 4,200,171, 4,287,328,4,316,966 and 5,122,583. The pre-polymerized catalysts can be preparedin the presence of cocatalysts, such as the ones described previouslyand optionally in the presence of various electron donors.

Preferred pre-polymerized metallocenes of the present invention have aweight ratio of polymer/metallocene of approximately 0.1–100; ratios ofless than 10 are particularly preferred. The syntheses are convenientlydone at room temperature or lower in low boiling solvents which arereadily evaporated in vacuo.

Experimental Part

PPA means polyphosphoric acid, the synthesis of which is described in F.D. Popp and W. E. McEwen, Chem. Rev., 58, 321 (1958); F. Uhlig and H. R.Snyder, Advances in Organic Chemistry, 1, 35 (1960).

EXAMPLE 1 Synthesis of bis(2-methylthiapentenyl)zirconium dichloride

a. Synthesis of 4,5-Dihydro-5-methyl-6H cyclopenta(b)thiphene-6-one

[The following is a modification of the procedure originally describedby O. Meth-Cohn, S. Gronowitz, Acta Chemica Scandinavica, 20 (1966)1577–1587.]

A solution containing thiophene (65.7 g. 781 mmol), methacrylic acid(66.56 g. 773 mmol), and methylene chloride (50 mL) were added dropwiseto a solution of PPA (prepared above) over a 1 h. period, whilemaintaining the temperature at 50° C. The reaction mixture was stirredan additional 2 h. then poured onto 1 L of ice (prepared in a 2 Lsep.funnel), and the organic layer collected with methylene chloride inhexane solution (30%, 100 mL) The organic layer was then washed withwater (250 mL), a saturated solution of sodium bicarbonate (2×250 mL),followed by water (2×250 mL). The organic layer collected in thisfashion was then dried over magnesium sulfate, filtered and dried invacuo yielding 93.5 g of a dark brown, slightly viscous oil. Furtherdistillation of this material produced 52.2 g (1 mmbar, 92° C.–98° C.)of the target material. Yield=44%. 1H NMR: CDCl₃ ppm; 7.85 (d, 1H), 6.95(d, 1H), 2.4–3.3 (m, 2H), 1.25 (d, 3H).

b. Synthesis of the 5-methyl-1-thiapentalenyl hydrazine

[The following is a modification of the procedure originally describedby Hendrich Volz and Henrich Kowarsch, Tet. Lett., 48 (1976) 4375].

Absolute ethanol (300 g) was treated with a vigorous stream of gaseoushydrochloric acid until saturated. Toluene-4-sulfono hydrazine (64 g.343 mmol) was added as a dry powder, forming a white slurry.4,5-Dibydro-5-methyl-6H-cyclopenta(b)thiphene-6-one (52.2 g. 343 mmol)was added dropwise over a 30 minute period. The solution turned to aclear, straw colored liquid, then formed a white precipitate which wascollected by filtration. The precipitate was washed with THF (800 mL)then dried in vacuo. Yield: 100 g (91.5%).

c. Synthesis of 5-methyl-1-thipentalene

5-methyl-1-thiapentalenyl hydrazine (12.8 g. 40 mmol) was slurried indiethylether (100 mL) and the temperature lowered to −78° C.Methyllithium (100 mmol, 1.6 M solution in diethylether, 62.5 mL) wasadded dropwise. The temperature was allowed to rise to ambient stirringwas continued for 16 h with the color turning deep purple. Adeoxygenated saturated aqueous ammonium chloride solution was addeddropwise (2 mL) and stirred for an additional 15 minutes, the color ofthe solution turning yellow. The slurry was then filtered through amedium porosity frit and the solids were washed repeatedly with freshdiethylether (250 mL). The diethylether in the filtrate was then removedin vacuo and a dark brown oil recovered (1.62 g. 30%). Mass spectrum(typical, first isomer; m/e (RA) 136 (11.4), 134 (100), 121 (25), 77(12).

d. Synthesis of bis(2-methylthiapentenyl)zirconium dichloride Zirconiumtetrachloride

(800 mg, 3.4 mmol) was added as a dry powder to5-methyl-1-thiapentalenyl lithium salt (400 mg, 3.6 mmol) and pentane(50 mL) and THF (5 mL) were added to make a slurry. The slurry wasstirred an additional 16 h. after which time the solvents were removedin vacuo and a bright yellow free flowing powder was recovered (1 g).Sample was used for polymerization without further purification. 1H-NMR(THF-d8): ppm, 7.4 (m, 1H), 7.0 (m, 1H), 5.9 (s, 1.5H), 5.7 (s, 1H), 2.1(s, 3H).

EXAMPLE 2

Ethylene Polymerization with bis(2-methylthiapentenyl)zirconiumdichloride

Ethylene polymerizations were run in a 500 mL glass reactor withindirectly coupled magnetic stirring. Catalyst (20 mg) was added to a 10mL glass vial and MAO was added (2.5 mL, 10 wt % in toluene). Anadditional 2.5 mL was added to the toluene solution used as thepolymerization solvent. The solution containing the catalyst/MAO wasadded to the reactor containing the toluene/MAO via cannula. The reactorwas purged of any residual nitrogen and replaced with ethylene. Ethylenewas added to the reactor and the pressure was maintained at 3 bar for 8minutes after which time the reaction was quenched with 5 mL ofdistilled water. The reactor contents were then poured into a deashingsolution containing HCI (4 N, 120 mL) and methanol (80 mL). The organiclayer was dried in vacuo under mild heat (50° C., 3 h).

Yield: 2.5 g; [η]THN=3.47 (dl/g).

EXAMPLE 3

Propylene Polymerization with bis(2-methylthiapentenyl)zirconiumdichloride

Propylene polymerizations were run in a 500 mL glass reactor withindirectly coupled magnetic stirring. Catalyst (20 mg) was added to a 10mL glass vial and MAO was added (5.0 mL, 10 wt % in toluene). Thereactor was purged of any residual nitrogen and replaced with propylene.Propylene was added to the reactor and the pressure was maintained at 3bar for 60 minutes after which time the reaction was quenched with 5 mLof distilled water. The reactor contents were then poured into adeashing solution containing 120 mL 4N HCI and 80 mL methanol. Theorganic layer was dried in vacuo under mild heat (70° C., 1 h).

Yield: 13.5 g viscous oil. [η]THN=0.18 (dl/g).

EXAMPLE 4 Synthesis of dimethylsilylbis(2-methylthiapentenyl)zirconiumdichloride

a. preparation of 5-methyl-1-thiapentalene:

The synthesis was carried out according to above described Example 1c.

b. Synthesis of dimethylsilylbis(2-methylthiapentenyl):

5-methyl-1-thipentalene (1.62 g. 11.9 mmol) was dissolved in 30 mL ofdiethylether and the temperature lowered to −78° C. Methyllithium (11.9mmol, 1.6M of a diethylether solution, 7.4 mL), was added dropwise. Theflask and contents were allowed to warm to room temperature and stirringwas continued for 3 h. In a separate flask, dimethyldichlorosilane (0.77g. 5.9 mmol, 0.78 mL) was dissolved in 20 mL of THF and the temperaturelowered to −78° C. The slurry containing the 5-methyl-1-thipentaleneanion was added dropwise to the stirred solution. The flask and contentswere then allowed to warm to room temperature. A sample was taken foranalysis, quenched with saturated solution of aqueous ammonium chloride,dried over magnesium sulfate, filtered, concentrated in vacuo, thensubmitted for analysis (20549-47C, 37.6% purity by GCMS). Mass spectrum(m/e (RA): 328 (18.7), 193 (100), 165 (29.1), 159 (36.7), 134 (53.4), 91(81.2), 59 (27.7), 43 (10.5).

c. Synthesis of dimethylsilylbis(2-methylthiapentenyl)zirconiumdichloride

A solution containing dimethylsilylbis(2-methylthiapentenyl) (1.78 g.5.95 mmol) in diethylether (prepared above) at −78° C. was treated withmethyllithium (11.9 mmol, 1.6M solution in diethylether, 7.4 mL). Thecontents were allowed to warm to room temperature and stirring wascontinued for 16 h. Solvents were removed in vacuo and the solids werewashed repeatedly with fresh pentane (3×30 mL). Zirconium tetrachloridewas added as a dry powder, and pentane was added. Pentane was thenevaporated and replaced with toluene and the solution was stirredovernight. The solids were filtered and the filtrate dried in vacuo.Yield: 1.49 g (54%).

EXAMPLE 5

Propylene Polymerization withdimethylsilylbis(2-methylthiapentenyl)zirconium dichloride

Propylene polymerizations were run in a 500 mL glass reactor withindirectly coupled magnetic stirring. Catalyst (20 mg) was added to a 10mL glass vial and MAO was added (5.0 mL, 10 wt % in toluene). Thereactor was purged of any residual nitrogen and replaced with propylene.Propylene was added to the reactor and the pressure was maintained at 3bar for 60 minutes after which time the reaction was quenched with 5 mLof distilled water. The reactor contents were then poured into adeashing solution containing 120 mL 4N HCl and 80 mL methanol. Theorganic layer was dried in vacuo under mild heat (700 C, I h).

Yield: 19.6 g white free flowing polymer, [η]THN=0.49 (dl/g).

EXAMPLE 6 Synthesis ofisopropylidene[cyclopentadienyl-(7-cyclopenadithiophene)]zirconiumdichloride

a. Synthesis of 7H-cyclopenta[1.2-b: 4.3-b′]dithiophene

7H-cyclopenta[1.2-b: 4.3-b′]dithiophene (referred to in the followingexamples as cyclopentadithiophene) was synthesized according to theprocedure originally described by A. Kraak et al, Tetrahedron, 1968, 24,3381–3398.

b. Isopropylidene(7H-cyclopentadithiophene)(cyclopentadiene).

A solution of cyclopentadithiophene (1.0 g. 5.62 mmol) in ether (15 mL)was cooled to −78 C and treated with n-butyllithium (5.75 mmol, 2.3 mLof 2.5 M solution in hexanes,). After stirring at 0° C. for 2 h. asolution of 6,6-dimethylfulvene (0.60 g, 5.62 mmol) in ether (5 mL) wasadded over a 30 minute period. The temperature was held at 0° C. for 1 hand then the contents were warmed to 25 C and stirred for 16 h. Thereaction was stopped by adding a solution of saturated NH₄Cl (15 mL).The organic layer was separated, washed with saturated salt solution(2×15 mL), and dried over MgSO₄. After filtration, solvents were removedby rotoevaporation to an oily residue. The product was crystallized froma mixture of methanol/acetone as a white solid (700 mg, 44%). Proton NMR(CDC1₃) ppm: (2 isomers) 7.23 (d. 2H), 7.10 (d. 2H), 6.1–6.8 (m, 3H),3.1 (m, 2H), 1.18, 1.29 (2s, 6H). Mass spectrum: C17H16S2 PM=284.

c. Isopropylidene[cyclopentadienyl-(7-cyclopenatadithiophene)]zirconiumdichloride.

A solution of isopropylidene(7H-cyclopentadithiophene)(cyclopentadiene)(540 mg, 1.9 mmol) in THF (20 mL) was cooled to −78 C and treated withn-butyllithium (4.0 mmol, 1.6 mL of 2.5 M solution in hexanes). Thereaction contents were slowly warmed to O C and stirring continued for 4h giving a dark red solution. Solvents were removed in vacuo at 0° C.and the residue was reslurried in ether (15 mL) at −78 C. ZrCl₄ (0.443g. 1.9 mmol) was added as a slurry in pentane (10 mL) by cannula and thereaction contents were slowly warmed to room temperature while stirringfor 16 h. The precipitated crude product was collected on a closed frit,washed with ether and pentane and dried in vacuo (yield: 1.0 g). Asample of the title compound used in polymerization tests was obtainedby extraction with toluene at 50° C.

Proton NMR (CD₂Cl₂) ppm, δ, 7.42 (d, 2H), 7.21 (d, 2H), 6.44 (t, 2H),5.84 (t, 2H), 2.05 (s, 6H).

EXAMPLE 7

Ethylene Polymerization withisopropylidene[cyclopentadienyl-(7-cyclopentadithiophene)]zirconiumdichloride

Ethylene polymerizations were run in a 500 mL glass reactor withindirectly coupled magnetic stirring. Catalyst (10 mg) was added to a 10mL glass vial and MAO was added (2.5 mL, 10 wt % in toluene). Anadditional 2.5 mL was added to the toluene solution used as thepolymerization solvent. The solution containing the catalyst/MAO wasadded to the reactor containing the toluene/MAO via cannula. The reactorwas purged of any residual nitrogen and replaced with ethylene. Ethylenewas added to the reactor and the pressure was maintained at 3 bar for 8minutes after which time the reaction was quenched with 5 mL ofdistilled water. The reactor contents were then poured into a deashingsolution containing HCI (4 N, 120 mL) and methanol (80 mL). The organiclayer was washed with water and polymer solids were collected byfiltration and washed with fresh methanol. The polymer was dried invacuo under mild heat (50° C., 3 h).

Yield: 4.3 g; I.V. (THN)=3.7 (dl/g).

EXAMPLE 8

Propylene Polymerization with isopropylidene[cyclopentadienyl-(7-cyclopentadithiophene)]zirconium dichloride

Propylene polymerizations were run in a 500 mL glass reactor withindirectly coupled magnetic stirring. Catalyst (20 mg) was added to a 10mL glass vial and MAO was added (5.0 mL, 10 wt % in toluene). Thereactor was purged of any residual nitrogen and replaced with propylene.Propylene was added to the reactor and the pressure was maintained at 3bar for 60 minutes after which time the reaction was quenched with 5 mLof distilled water. The reactor contents were then poured into adeashing solution containing 120 mL 4N MCI and 80 mL methanol. Theorganic layer was washed with water and solvents removed on arotoevaporator. The viscous polymer was dried in vacuo under mild heat(50 C, 1 h) Yield: 30 g polymer, I.V. (THN)=0.30 (dl/g).

EXAMPLE 9 Synthesis ofisopropylidene[(t-butylcyclopentadienyl)-(7-cyclopentadithiophene)]zirconiumdichloride

a. Synthesis of 7H-cyclopenta[1.2-b: 4.3-b′]dithiophene

7H-cyclopenta[1.2-b: 4.3-b′]dithiophene (referred to in the followingexamples as cyclopentadithiophene) was synthesized according to theprocedure originally described by A. Kraak et al, Tetrahedron, 1968, 24,3381–3398.

b. preparation of 3-t-butyl-6,6-dimethylfulvene

Dry acetone (99.3 mmol, 5.77 g, 7.3 mL) and t-butylcyclopentadiene (50.6mmol, 6.17 g) were mixed in a dropping funnel and added at roomtemperature to an ethanol solution (10 mL) of KOH (10.3 mmol, 0.58 g)stirring under nitrogen. After stirring overnight, the golden solutionwas diluted with ether, washed with 2 N HCl, water, and dried oversodium sulfate. A sample of the crude organic fraction (7.4 g) was takenfor analysis (GCMS) showing 90% conversion to the title compound. Theproduct was submitted to distillation. ¹H-NMR (CDCl₃): δ 1.38 (s, 9H),2.28 (s, 6H), 6.24 (m, 1H), 6.63 (m, 2H).

c. synthesis ofisopropylidene(3-t-butylcyclopentadienyl)(7H-cyclopentadithiophene).

A solution of cyclopentadithiophene (4.9 mmol, 0.87 g) in dry ether wascooled to −78° C. and treated with n-butyllithium (4.9 mmol, 1.95 mL of2.5 M solution in hexane). The reaction mixture was warmed to 0° C. andstirred for 4 h. A solution of 3-t-butyl-6,6-dimethylfulvene (4.9 mmol,0.79 g) in ether (10 mL) was added dropwise, stirred for 2 h at 0° C.,and then at room temperature for 16 h. The reaction was quenched by slowaddition of a saturated solution of NH₄Cl (10 mL). The aqueous layer wasseparated, washed with ether and discarded. The organic fractions werecombined, dried over MgSO₄, filtered, and evaporated to an oil. The oilwas redissolved in a mixture of methanol/acetone and the product wascrystallized by cooling on dry ice. Yield: 800 mg, 48%.

d. Isopropylidene[t-butylcyclopentadienyl-(7-cyclopentadithiophene)]zirconium dichloride

Isopropylidene[t-butylcyclopentadienyl-(7-cyclopentadithiophene)] (800mg, 2.4 mmol) was dissolved in THF (20 mL). The temperature was loweredto −78° C. and n-butyllithium (4.8 mmol, 1.92 mL of a 2.5 M solution inhexane) was added dropwise. The solution turned dark brown, was stirredan additional 10 minutes at −78° C., and allowed to slowly rise toambient temperature. After gas evolution had stopped (2 h) stirringcontinued for 1 h before. THF was removed under pressure. The solidswere washed with pentane and dried in vacuo. ZrCl₄ (2.5 mmol, 0.56 g)was added and the mixture of solids were suspended in pentane (50 mL)and stirred for 16 h. Then, pentane was decanted off and the productdried in vacuo yielding 1.21 g of a light brown free flowing powder. Theproduct (1.2 g) was slurried in 30 mL Me₂Cl₂. After filtering and dryingin vacuo 150 mg of the complex was isolated. ¹H-NMR ppm: δ 7.40 (d, 2H),7.22 (m, 2H), 6.30 (t, 1H), 5.85 (t, 1H), 5.65 (t, 1H), 2.0 (s, 6H), 1.2(s, 9H).

EXAMPLE 10

Propylene Polymerization withisopropylidene[t-butylcyclopentadienyl-(7-cyclopentadithiophene)]zirconiumdichloride

Propylene polymerizations were run in a 250 mL glass reactor withindirect coupled magnetic stirring, internal temperature probe, andexternal temperature bath. The reactor was charged with toluene (100 mL)and MAO (3 mL, 10 wt/% solution in toluene from Witco Corp., 4.7 wt %Al). The contents was thermostated at 50° C. under stirring. The desiredamount of a calibrated metallocene/toluene solution was added andstirred for 5 minutes. Propene gas was added to the desired pressure.Monomer pressure and temperature were kept constant during the run. Thereaction was stopped after 1 h by venting the pressure and adding 5 mLof acidified methanol. The contents of the reactor were quantitativelytransferred into an acidified methanol solution under vigorous stirringfor several minutes before separating the organic fraction. Afterthorough washing with water, solvents were removed by rotoevaporation.The polymer was dried in vacuo under mild heat. Yield: 28 g polymer.I.V. 0,3 dl/g; mp.: 128° C.; mrrm: 2.9 mol %.

EXAMPLE 11 Synthesis ofbis(4-phenyl-2,6-dimethyl-thiopentalene)zirconium dichloride

a. Preparation of 3,4-bischloromethyl-2,5-dimethylthiophene

In a 2 L round bottom flask equipped with 100 ml dropping funnel andmechanical stirring was added 2,5-dimethylthiophene (253.6 g, 2.26 mmol)and HCl (41.3 g, 1.13 mol, 94.5 mL of a 37 wt % solution). HCl gas wasadded in a slow stream for 5 minutes prior to the dropwise addition of asolution containing (aqueous) formaldehyde (69.1 g, 2.3 mol, 172 mL of a37 wt % solution). The temperature was maintained between −15° C. and 0°C. during the course of addition (1 h 20 min). After completion of theaddition, the contents was stirred an addition 1 h. The reaction mixturewas quenched with H2O (400 mL), and the organic layer collected withdiethylether (400 mL). The organic layer was washed with a saturatedsolution containing Na2CO3, water, dried over magnesium sulfate,filtered, then the solvents were removed in vacuo to yield 349.0 g ofreaction product. Further purification by vacuum fractional distillationat 190 mtorr yields to 60.54 of the desired product.

b. Synthesis of 4-phenyl-2,6-dimethyl-thiopentalene-4-ol

In a 2 L round bottom flask with mechanical stirring was added magnesiumpowder (29 g, 1.2 mol) and covered with THF (20 mL). Then the turningswere activated with 5 crystals of iodine and dibromoethane (1.5 mL).After activation was complete, THF was removed and replaced with freshTHF. A solution containing 3,4-bis-chloromethylthiophene (42.8 g, 205mmol) in THF (1 L) was added dropwise and stirred for additional 18 h. Asolution containing Methylbenzoat (29 g, 213 mmol) dissolved in THF (220mL) was added dropwise to the rapidly stirred solution and the mixturewas stirred an additional 5 h. The reaction mixture was then quenched byadding a mixture of THF/water, then H2O (200 mL) was added and theorganic fraction was collected with dry diethylether. The organic layerwas then dried over MgSO4, filtered, and the solvents were removed undervacuum to yield 61.9 g of a bright orange oil, containing 57% of thedesired product. (71% isolated yield).

c. Synthesis of 4-phenyl-2,6-dimethyl-thiopentalene

In a 2 L round bottom flask with reflux condenser was placed the alcoholto be dehydrated (45.9 g) was dissolved in toluene (100 mL).Paratoluensulfonic acid monohydrate (1.6 g) and 1 g Amberlite IR-120were added. The contents were heated to reflux for 4 h, then the flaskand the contents were allowed to cool to room temperature. The organiclayer was collected, washed repeatedly with H2O, dried over MgSO4. Afterfiltration, the solvent was removed by rotoevaporation to yield 41.45 gof a dark brown oil.

d. Synthesis of bis(4-phenyl-2,6-dimethylthiopentalene)zirconiumdichloride

In a 100 mL round bottom flask with stirring bar and sidearm was added a80% mixture (2.8 g, 10 mmol) containing4-phenyl-2,6-dimethyl-3-ene(b)thiophene. The complex was dissolved indry diethylether (50 mL), then n-butyllithium (12.5 mmol, 5 mL of a 2.5M solution) was added dropwise at room temperature. The mixture wasstirred for 1 h forming a bright orange solid precipitate which wascollected by removing the solvent in vacuo. Zirconium tetrachloride(1.16 g, 5 mmol) was added and the solids were suspended in pentane (50mL). The reaction mixture was stirred for 18 h, then the solids werecollected by filtration, washed with fresh pentane, and dried in vacuo.A portion of the solids collected in this fashion were dissolved intoluene, then filtered. The toluene was removed in vacuo and 1.38 g of adark red glassy free flowing solid was collected. 1H-NMR: δ ppm: 7.25(m, 10H), 5.78 (s, 4H), 2.44 (s, 6H).

EXAMPLE 12

Propylene Polymerization withbis(4-phenyl-2,6-dimethylthiopentalene)zirconium dichloride

A 250 mL glass reactor bottle was charged with 100 mL toluene. Asolution containing bis(4-phenyl-2,6-dimethylthiopentalene)zirconiumdichloride (5 mg), and MAO (5 mL, 10 wt % in toluene) was added. Thereactor was sealed and the pressure was raised to 4 bar with propylenegas. Temperature was controlled at 40° C. during the polymerization.After 1 h, the reactor was purged with nitrogen and the solutionquenched with an aqueous solution containing 30% (v/v) HCl (37 wt %) and30% methanol. After filtration of the toluene soluble material, thesolvent was removed in vacuo. Yield: 300 mg polymer.

% m=75.4; η=512 (by NMR).

EXAMPLE 13 Preparation ofdimethylsilylbis(1-phenyl-2,5-dimethyl-1-azapentalene-4-yl)zirconiumdichloride

a. Synthesis of 1-phenyl-2-methylpyrrole I

Butyllithium (0.700 mol, 280 mL of 2.5 M solution in hexane) was addedslowly at room temperature to a mixture of 1-phenylpyrrole (0.695 mol,100 g) and TMEDA (0.700 mol, 106 mL) in hexane (80 mL) and stirred for 3h. The slurry was diluted with 300 mL of THF and iodomethane (0.771 mol,48 mL) was added slowly maintaining the temperature between 35–40° C.After stirring at room temperature for 16 h, 250 mL of water were addedand the organic layer was separated. The aqueous layer was extractedwith ether (2×100 mL) and the combined organic fractions were dried overMgSO₄. After filtration, evaporation of solvents and TMEDA yielded 107 gof light brown oil (98% yield, +95% purity by GC). ¹H-NMR δ (CDCL₃):7.29–7.44 (m, 5H), 6.80 (m, 1H), 6.23 (m, 1H), 6.08 (m, 1H), 2.24 (s,3H).

b. Synthesis of 1-phenyl-5-methyl-2-pyrrolecarboxaldehyde II

POCl₃ (0.375 mol, 35 mL) was added dropwise to 37 mL of DMF and stirredfor 10 min. The temperature was lowered to 0° C. and a mixture of I (55g, ca. 0.340 mol) and DMF (7 mL) was added dropwise. The viscoussolution was slowly warmed to 50° C. and stirred for 1 h. After coolingto room temperature, the flask was opened to the air and charged with350 g of crushed ice. A 20 wt % solution of NaOH (430 mL) was addedcautiously and the mixture was immediately heated to 90–95° C. andstirred for 10 min. The flask was placed in an ice bath and the productsolidified upon cooling. The solids were collected on a filter funnel,washed with water, redissolved in dichloromethane, and dried over MgSO₄.After filtration, evaporation of the solvent yielded 38 g of light brownsolids (60% yield). ¹H-NMR showed the crude product to be a mixture of1-phenyl-5-methyl-2-pyrrolecarboxaldehyde and1-phenyl-2-methyl-3-pyrrolecarboxaldehyde in ca. 4:1 ratio.Spectroscopically pure 1-phenyl-5-methyl-2-pyrrolecarboxaldehyde wasobtained by recrystallization from ether.

The assignment of the two isomers was confirmed by NOESY NMR experiment.

¹H-NMR δ (CDCL₃) of 1-phenyl-5-methyl-2-pyrrolecarboxaldehyde: 9.26 (s,1H, Py-COH), 7.43 (m, 3H, ArH), 7.22 (m, 2H, ArH), 7.00 (d, 1H, PyH),6.12 (d, 1H, PyH), 2.04 (s, 3H, PyCH₃), mp 85° C. ¹H-NMR δ (CDCL₃) of1-phenyl-2-methyl-3-pyrrolecarboxaldehyde: 9.88 (s, 1H, PyCOH), 7.43 (m,3H, ArH), 7.22 (m, 2H, ArH), 6.68 (d, 1H, PyH), 6.62 (d, 1H, PyH), 2.39(s, 3H, PyCH₃).

c. Synthesis of Ethyl β-(1-phenyl-2-methylpyrrol-5-yl)methacrylate (III)

Triethyl 2-phosphonopropionate (93.3 mmol, 20 mL) was diluted with THF(15 mL) and added slowly to NaH (130 mmol, 3.16 g) in THF (40 mL) at 0°C. Stirring was continued at room temperature for 30 min. after gasevolution had ceased. The temperature was lowered to −10° C. and asolution of (II) (86.5 mmol, 16.0 g) in 50 mL THF was added dropwise.The flask and contents were warmed to room temperature over a 30 min.period resulting in a thick precipitate which decoupled the magneticstirrer. A saturated solution of NH₄Cl (50 mL) was added cautiouslydissolving the precipitate. After evaporating THF, the crude product wasextracted with ether (2×100 mL), washed with brine solution, dried overMgSO₄, filtered and evaporated to a brown oil. Yield: 22.5 g (96.5%) ofspectroscopically pure product. ¹H-NMR (CDCl₃): 7.41 (m, 3H, ArH), 7.15(m, 3H, ArH (2 H's)+PyCHC(CH₃) (CO₂Et)), 6.60 (d, 1H, PyH), 6.12 (d, 1H,PyH), 4.04 (q, 2H, OCH₂CH₃), 2.09 (s, 3H, PyCHC(CH₃)(CO₂Et)), 2.00 (s,3H, PyCH₃), 1.12 (t, 3H, OCH₂CH₃).

d. Synthesis of Ethyl β-(1-phenyl-2-methylpyrrol-5-yl)isobutyrate (IV)

A solution of (III) (10 g, 37 mmol) in ethanol (50 mL) was stirred under3.5 bar of hydrogen pressure at room temperature with 300 mg of 10% Pdon carbon for 1 h. Evaporation of the filtered golden solution gaveethyl β-(1-phenyl-2-methylpyrrol-5-yl)isobutyrate as a yellow syrup (9.4g, 95% pure by GC). ¹H-NMR δ (CDCl₃): 7.43 (m, 3H, ArH), 7.23 (m, 2H,ArH), 5.92 (m, 2H, PyH), 4.00 (q, 2H, OCH₂CH₃), 2.70 (m, 1H,PyCH₂CH(CH₃)(CO₂Et)), 2.46 (m, 2H, PyCH₂CH), 2.00 (s, 3H, PyCH₃), 1.21(t, 3H, OCH₂CH₃), 1.05 (d, 3H, CH(CH₃)(CO₂Et)). ms (m/e) (rel intensity)271 ([M⁺], 23), 170 (100), 154 (12), 128 (6), 77 (10).

e. Synthesis of Ethyl β-(1-phenyl-2-methylpyrrol-5-yl)isobutyric acid(V)

A mixture of (IV) (9.4 g of crude oil, ca. 33 mmol) and Claisen'sreagent (18 mL) were heated at 90–95° C. for 1 h. After cooling to roomtemperature, the solution was diluted with 15 g of crushed ice andacidified to pH 1–2 with 6 N HCl. The brown oily precipitate wasdissolved in ether, washed with brine solution, dried over MgSO₄,filtered and evaporated to waxy solids. Triteration of the solids withpentane afforded 6.6 g of V as a tan powder (84.7% yield).

¹H-NMR δ (CDCl₃): 7.43 (m, 3H, ArH), 7.21 (m, 2H, ArH), 5.92 (m, 2H,PyH), 2.72 (dd, 1H, PyCH₂CH(CH₃)(CO₂Et)), 2.46 (m, 2H, PyCH₂CH), 2.00(s, 3H, PyCH₃), 1.05 (d, 3H, PyCH₂CH(CH₃)).

f. Synthesis of1-phenyl-5,6-dihydro-2,5-dimethylcyclopenta[b]azaphene-4-one (VI)

A solution of (V) (25 mmol, 6.0 g) in dichloroethane (45 mL) was addedslowly to 100 g of 87% PPA at 85–90° C. and stirred for 3 h. The mixturewas cooled to room temperature, 200 g of crushed ice were added, andstirring continued until all PPA had dissolved. The lower organic layerwas separated and the aqueous layer was extracted with dichloromethane.The combined organic fractions were washed with K₂CO₃, brine solution,dried over MgSO₄, filtered and evaporated to an oil which solidifiedupon standing for 16 h. The solids were triterated with hexane/ether anddried under vacuum. Yield 2.85 g of white powder (51%). ¹H-NMR δ(CDCl₃): 7.44 (m, 3H, ArH), 7.23 (m, 2H, ArH), 6.12 (s, 1H, PyH), 2.90(m, 2H, PyCH₂), 2.32 (d, 1H, PyCH₂CH(CH₃)CO—), 2.09 (s, 3H, PyCH₃), 1.19(d, 3H, PyCH₂CH(CH₃)CO—). ms (EI) (rel intensity): 223 ([M⁺−2], 4), 205(4), 149 (100), 121 (3), 104 (5), 93 (3), 76 (5). mp 106° C.

g. Synthesis of the Hydrazone of the Ketone (VII)

The ketone (VI) (31 mmol, 7.0 g), p-toluenesulfonhydrazide (36 mmol, 6.7g), and p-toluenesulfonic acid monohydrate (6.3 mmol, 1.2 g) weredissolved in 50 mL of absolute ethanol and stirred at 65° C. for 24 h.After cooling to room temperature and standing for several hours, theprecipitated product was collected on a filter funnel, washed with etherand dried under vacuum (yield 5.0 g) Solvents were removed from thefiltrate and an additional 1.2 g of product were crystallized from anether/toluene solution of the oily residue. Total yield: 6.2 g (51%) oflight gray powder.

¹H-NMR δ (CDCl₃): 7.80 (d, 2H, ArH), 7.39 (m, 3H, ArH), 7.17 (m, 4H,ArH), 6.23 (s, 1H, PyH), 3.25 (tt, 1H, PyCH₂CH(CH₃)CN—), 2.89 (dd, 1H,PyCH₂), 2.35 (s, 3H, PyCH₃), 2.24 (dd, 1H, PyCH₂), 2.10 (s, 3H, Me),1.15 (d, 3H, PyCH₂CH(CH₃)CN—). mp 156 ° C. (dec).

h. Synthesis of 1-phenyl-2,5-dimethyl-1-azapentalene (VIII)

The hydrazone (VII) (12.7 mmol, 5.0 g) was slurried in 20 mL of THF,cooled to 0° C., and treated with 2.1 eq of butyllithium (10.6 mL of 2.5M BuLi in hexane). The mixture was slowly warmed to room temperature andan additional 10 mL of THF were added giving a dark solution. After 2 h,precipitates had formed and ether was added (ca. 30 mL) to furtherprecipitate the product. The solids were collected on a closed filterfunnel, washed with ether, and dried in vacuo (7.5 g). ¹H-NMR of thecrude product, protonated with wet CDCl₃, showed a mixture of twoisomers. The solids were suspended in hexane (100 mL) and treated with asaturated solution of NH₄Cl. The hexane layer was separated, dried overMgSO₄, filtered and evaporated to an oil (1.0 g yield, 85% purity byGC/MS). Proton NMR of the oil showed a single isomer. ¹H-NMR δ (CDCl₃):Isomer 1—7.33 (m, 5H, ArH), 5.96 (s, 1H), 5.86 (s, 1H) 3.15 (s, 2H, CH₂of C₅ ring), 2.21 (s, 3H, PyCH₃), 2.04 (s, 3H, CH₃ at C-5). Isomer2—7.33 (m, 5H, ArH), 6.11 (s, 1H), 5.85 (s, 1H), 3.15 (s, 2H, CH₂ of C₅ring), 2.18 (s, 3H, PyCH₃), 2.00 (s, 3H, CH₃ at C-5). me (EI) (relintensity): 209 (100), 194 (27), 167 (5), 117 (4), 91 (5), 77 (13).

(i) Synthesis of dimethylsilylbis(4-phenyl-2,5-dimethyl-4-azapentalene)(IX)

1-phenyl-2,5-dimethyl-1-azapentalene (7.18 mmol, 1.5 g) was dissolved inether (40 mL), cooled to −78° C., and treated with 7.5 mmol ofbutyllithium (3 mL of a 2.5M solution in hexanes).

The solution was warmed to room temperature and stirred for 2 h. Theprecipitated lithium salt was collected on a closed filter funnel,washed with pentane, and dried in vacuo. The salt (700 mg) wasredissolved in THF (40 mL), cooled to −78° C. and 0.2 mL (1.63 mmol) ofdichlorodimethylsilane was injected with a gas tight syringe. Thesolution was heated to 55° C. and stirred for 16 h. Solvents wereremoved in vacuo and the crude product was used without furtherpurification (The ligand was obtained as a mixture of isomers). ¹H-NMR δ(CD₂Cl₂): 7.42–7.62 (m, 10H, ArH), 6.45, 6.42, 6.21, (3 s, 4H), 5.86 (s,1H,) 3.62 (s, 2H), 2.48, 2.45, 2.43, 2.41 (4 s, 12H), −0.06, −0.08,−0.11 (3 s, 6H). ¹³C-NMR (CD₂Cl₂): 129.4, 126.4, 126.1 (Ar), 117.9,104.6 (olefinic CH), 42.5 (CH), 18.0 (CH₃), 14.3 (CH₃), −7.1, −7.3, −7.6(Si—CH₃). me (EI) (rel intensity): 474 (29), 266 (100), 251 (11), 208(21), 192 (13), 77 (5).

(ii) Synthesis ofdimethylsilylbis(4-phenyl-2,5-dimethyl-4-azapentalenyl)zirconiumdichloride (X).

Product IX (1.1 g) was dissolved in ether (20 mL), cooled to −78° C.,and treated with 4.8 mmol of butyllithium (1.9 mL of a 2.5M sol. inhexanes). The solution was warmed to room temperature and stirred for 16h. The precipitated dianion was collected on a closed filter funnel,washed with pentane and dried in vacuo to a tan powder (0.7 g). Thedianion was mixed with 0.32 g of ZrCl₄, cooled to −78° C., and treatedwith 20 mL of cold dichloromethane (−78° C.). The flask and contentswere slowly warmed to room temperature, stirred for 4 h, and filtered.The filtrate was evaporated to a brown free flowing powder and used inpolymerization tests without further purification.

EXAMPLE 14

Propylene polymerization withdimethylsilylbis(4-phenyl-2,5-dimethyl-4-azapentalene-4-yl)zirconiumdichloride

Propylene polymerizations were run in a 250 mL glass reactor withindirect coupled magnetic stirring, internal temperature probe, andexternal temperature bath. The reactor was charged with 100 mL oftoluene. 10 mg of X in 5 mL of toluene were mixed with 3 mL of MAO (10wt % solution in toluene from Witco Corp., 4.7 wt % Al) and charged tothe reactor stirring at 25° C. The reactor was pressured to 4 bar withpropylene and the temperature was raised to 50° C. The polymerizationwas stopped after 1 h by venting the pressure and injecting 5 mL ofacidified methanol. The contents of the reactor were transferred into anacidified methanol solution under vigorous stirring for several minutes.After separating the organic fraction and washing with water, solventswere evaporated and the polymer was dried under vacuum and mild heat.Yield=15 g of free flowing powder (Mw=47,000, DSC melting point=153° C.,¹³C-NMR mrrm pentad=0.6 mol %).

EXAMPLE 15 Synthesis ofdimethylsilyl(2-methylthiopentalene)(2-methylindene)zirconium dichloride

a. Synthesis of dimethylsilyl(2-methylthiopentalene)chloride

In a 500 mL round bottom flask equipped with sidearm, stirring bar, and125 mL dropping funnel was added 31.9 g (100 mmol) of the asymmetricthiopentahydrazine dissolved in THF (70 mL). N-Butyllithium (250 mmol,100 mL of a 2.5 M solution in hexane) was added dropwise. The reactionwas stirred for an additional 5 h. after addition was complete. Thereaction was then quenched with 250 mmol water (4.5 mL H₂O in 50 mLEt₂O). The organic layer was collected with Et₂O, dried over magnesiumsulfate, filtered, then rotary evaporated to give a dark brown oil.

Results: area % BTR 7.6% PM = 136 79.6% ATR 12.8%

In a 250 mL round bottom flask with sidearm, stirring bar, and 60 mLdropping funnel was added the olefin (10 g, 73.5 mmol) prepared above,dissolved in THF (15 mL). N-Butyllithium (73.5 mmol, 29.4 mL of a 2.5 Msolution in hexane) was added dropwise, and the reaction was stirred for16 hours. Then the solvents were removed in vacuo and the solids werewashed with pentane. In a separate 500 mL flask equipped with 125 mLdropping funnel was prepared dimethyldichlorosilane (19.3 g, 150 mmol,18.2 mL, 1.5 eq.) dissolved in THF (30 mL). The anion prepared above wasdissolved in THF (125 mL) and added dropwise to the silane solution. Thereaction mixture was stirred 30 minutes after addition was complete,then the solvents were removed in vacuo. An orange oil with orangesolids was recovered.

b. Synthesis of dimethylsilyl(2-methylindenyl)(2-methylthiopentalene)

In a 250 mL round bottom flask with sidearm, stirring bar, and 60 mLdropping funnel was added 2-methylindene (13 g, 100 mmol, product madeby Boulder) dissolved in THF (20 mL). N-Butyllithium (100 mmol, 40 mL ofa 1.6 M solution in hexane) was added dropwise at room temperature.After addition was complete, the flask and contents were stirred anadditional 2 h. A solution containingdimethylsilyl(2-methylthiopentalene)chloride in THF (30 mL) was addeddropwise at room temperature. Stirring was continued for 1 hour, afterwhich time the reaction was quenched with 30 mL of a 30% water/THFmixture, concentrated on a rotary evaporated, and a sample submitted foranalysis.

Results from GC of total reaction product:

BTR  0.7 PM = 130 61.9% (2-methylindene starting material) MTR  1.6% PM= 322 31.7% (target) ATR  4.1%

Mass spectrum (m/e(RA): 322 (34), 193 (100), 187 (37), 159 (37), 128(26).

Further purification of this material was carried out byrecrystallization from dichloromethane/MeOH. The solid materialrecovered in this fashion was then dried on the rotary evaporator.Results:

BTR: 0.7 (area %) PM = 130 10.2 MTR 27.6 PM = 322 48.5 PM = 328 6.3 ATR6.4c. Synthesis ofdimethylsilyl(2-methylthiopentalene)(2-methylindene)zirconium dichloride

In a 250 mL flask with sidearm and stirring bar was added thedimethylsilyl(2-methylindenyl)(2-methylthiopentalene) ligand (3.1 g, 9.6mmol) dissolved in THF (70 mL). The temperature was reduced to −30° C.and n-butyllithium (20 mmol, 8 mL at 2.5 M in hexanes) was addeddropwise. The reaction was stirred for 2 h after which time the solventwas removed in vacuo and the dianion collected in this fashion waswashed with fresh pentane, then dried in vacuo. The dianion was takeninto the dry-box and ZrCl₄ (2.23 g, 9.6 mmol) was added as a dry powder.The solids were then suspended in fresh pentane (70 mL) and stirred for16 hours. Then the solvents were decanted and then the solids were driedin vacuo. The solids were then dissolved in dichloromethane andfiltered. The dichloromethane was then removed in vacuo and the solidswere washed with fresh pentane. The solids were again dried in vacuo,then dissolved in toluene and filtered. The toluene was removed in vacuoand 1.6 g of a dark brown free flowing solid was recovered.

EXAMPLE 16

Propylene Polymerization withdimethylsilyl(2-methylthiopentalene)(2-methylindene)zirconium dichloride

In a 250 mL glass reactor was placed toluene (100 mL), catalyst (40 mg),and MAO (8 mL, 10 wt % in toluene). The reactor was sealed, then purgedwith propylene before raising the pressure to 4 bar. The polymerizationreaction was controlled at 60° C. for 1 h. The reactor was then purgedwith nitrogen, and an acidic methanol solution was used to quench thereactor contents. The organic layer was collected, washed with water,then dried in vacuo. Yield: 38 g white non-sticky free flowing polymer.

In a 250 mL glass reactor was placed toluene (100 mL), catalyst (5 mg),and 5 mL MAO (10 wt % in toluene). The reactor was sealed, then purgedwith propylene before raising the pressure to 4 bar. The polymerizationreaction was controlled at 60° C. for 1 h. The reactor was then purgedwith nitrogen, and an acidic methanol solution was used to quench thereactor contents. The organic layer was collected, washed with water,then dried in vacuo. Yield: 13 g white non-sticky free flowing polymer:% m=84.6, M_(n)=1132 (by NMR end group analysis).

EXAMPLE 17 Preparation ofdimethylsilyl(2-methylthiopentalenyl)(1-phenyl-2,5-dimethyl-1-azapentylenyl)zirconiumdichloride

a. Preparation of thio(c)penta-4-methyl-5-dimethylsilylchloride

In a 250 mL round bottom flask with sidearm, stirbar and 25 mL droppingfunnel was places 6.18 g (45.4 mmol, 6 mL) of 2-methylthiopentalene(2-MeTp) dissolved in 30 mL diethylether. The temperature of thesolution was reduced to −78° C. and 50 mmol n-butyllithium was added (20mL, 2.5 M solution in hexane). The solution was warmed to roomtemperature, then stirred an additional 2 h. A yellow solid precipitate(anion, lithium salt of the 2-MeTp) was formed in the reaction flask,which was cooled to −78° C. A solution containing 11.7 g (91 mmol)dimethyldichlorosilane dissolved in 20 mL diethylether was addeddropwise to the stirred reaction mixture. The flask and contents wereallowed to warm to room temperature and stirred an additional 18 h. Thecrude reaction mixture was then filtered and the solvents were removedin vacuo producing a dark orange oil. Yield: 10.45 g: ¹H-NMR CD₂Cl₂(major isomer): s ppm: 7.2 (d,1H), 7.1 (d, 1H), 6.7 (m, 1H), 3.6 (s,1H),2.3 (s,3H), 0.4 (s, 3H), 0.3 (s, 3H).

b. Preparation ofdimethylsilyl(2-methylthiopentalene)(1-phenyl-2,5-dimethyl-1-azapentalene)

In a 250 mL round bottom flask with sidearm and stirbar was added 1.86 g(6.4 mmol) of the lithium salt of 1-phenyl-2,5-dimethyl-1-azapentalene(previously prepared), dissolved in 30 mL diethylether. A solutioncontaining 1.46 g (6.4 mmol)thio(c)penta-4-methyl-5-dimethylsilylchloride dissolved in 30 mL diethylether was slowly added at room temperature and stirred an additional 48h. The reaction was then quenched with a solution containing 10%water/THF, the organic layer was collected, dried over magnesiumsulfate, filtered, then the solvents were removed in vacuo. Yield: 3.23g of a dark brown oil: ¹H-NMR CD₂Cl₂ (major isomer): s ppm: 7.5 (m, 5H),7.28 (d, 1H), 7.1 (d, 1H), 7.0 (d, 1H), 6.9 (m, 1H), 5.9–6.3 (m, 1H),3.0–3.3 (3s, 4H), 2.1–2.3 (m, 6H), 1.5 (s), 0.2 (m, 6H).

c. Preparation ofdimethylsilyl(2-methylthiopentalenyl)(1-phenyl-2,5-dimethyl-1-azapentylenyl)zirconiumdichloride

In a 250 mL round bottom flask with sidearm and stirbar was added 2.8 g(7 mmol)dimethylsilyl(2-methylthiopentalene)(1-phenyl-2,5-dimethyl-1-azapentalene)ligand (prepared above) dissolved in 50 mL diethylether. Dropwise,n-butyllithium was added (14 mmol, 6 mL of a 2.5 M solution in hexane),and the crude reaction mixture was stirred an additional 2 h at roomtemperature. The solvent was then removed in vacuo and the remainingsolids were washed with pentane. Zirconium tetrachloride (1.63 g, 7mmol) was added as a solid, then the solids mixture was suspended in 70mL fresh pentane. The contents of the reaction flask was stirredovernight. The solvents were evaporated, the solids collected in thisfashion were suspended in toluene, filtered, and the toluene removed invacuo to yield 660 mg of a light brown free flowing solid (mixture ofisomers, rac/meso).

EXAMPLE 18

Propylene Polymerization withdimethylsilyl(2-methylthiopenta-yl)(1-phenyl-2,5-dimethyl-1-azapentylene-yl)zirconiumdichloride

In a 250 mL glass reactor was placed 100 mL toluene, 5 mg catalyst, and5 mL MAO (10%). The reactor was sealed, then purged with propylenebefore raising the pressure to 4 bar. The polymerization reaction wascontrolled at 50° C. for 1 h. The reactor was then purged with nitrogen,and an acidic methanol solution was used to quench the reactor contents.The organic layer was collected, washed with water, then dried in vacuo.Result: 22.8 g polymer.

1. A metallocene of formula (I):Y_(j)R″_(i)Z_(jj)MeQ_(k)P_(l)  (I) wherein (1) Y is a coordinating groupcontaining a six π electron central radical directly coordinating Me towhich radical is fused one or more rings containing at least onenon-carbon atom selected from B, N, O, Al, P, S, Ga, Ge, As, Se, In, Sn,Sb, and Te; (2) R″ is a divalent bridge between the Y and Z groups; (3)Z is a coordinating group having the same meaning as Y or is an openpentadienyl containing group, a cyclopentadienyl containing group, aheterocyclopentadienyl containing group, a nitrogen containing group, aphosphorous containing group, an oxygen containing group, or a sulfurcontaining group; (4) Me is an element belonging to Group 3, 4, 5, 6, orto the lanthanide or actinide series of the Periodic Table of theElements; (5) Q is a linear or branched, saturated or unsaturated alkylradical, aryl radical, alkylaryl radical, arylalkyl radical, or ahalogen atom; (6) P is a stable non-coordinating or pseudonon-coordinating counterion; (7) i is an integer having a value of 0 or1; (8) j is an integer having a value from 1 to 3; (9) jj is an integerhaving a value from 0 to 2; (10) k is an integer having a value from 1to 3; and (11) l is an integer having a value from 1 to
 2. 2. Ametallocene according to claim 1, wherein Y contains one heterocyclicring fused to the central six π electron central radical.
 3. Ametallocene according to claim 2, wherein Y is a substitutedcyclopentadienyl group of formula:

wherein the groups R^(a), are identical or different from each other,are selected from the group consisting of hydrogen, linear or branched,saturated or unsaturated C₁–C₂₀ alkyl, C₃–C₂₀ cycloalkyl, C₆–C₂₀ aryl,C₇–C₂₀ alkylaryl and C₇–C₂₀ arylalkyl radicals, and wherein at least twoadjacent R^(a) groups form a condensed heterocyclic C₅–C₇ ringcontaining at least one non-carbon atom selected from B, N, O, Al, P, S,Ga, Ge, As, Se, In, Sn, Sb, and Te; R^(b) is hydrogen, halogen, linearor branched, saturated or unsaturated, C₁–C₂₀ alkyl, C₁–C₂₀ alkoxyl,C₆–C₂₀-aryl, C₇–C₂₀ alkylaryl, C₇–C₂₀ arylalkyl C₁–C₂₀ acyloxyl group,optionally containing a silicon atom, or R^(b) is the bridging divalentgroup R″.
 4. The metallocene according to claim 1, wherein Y contains atleast two heteroatoms.
 5. The metallocene according to claim 1, whereini is 1, j is 1, and Z has the same meaning as Y.
 6. A metalloceneaccording to claim 1, wherein i is 1, j is 1, and Z is acycolpentadienyl containing group, an open-pentadienyl containing group,a nitrogen containing group, a phosphorus containing group, an oxygencontaining group, or a sulfur containing group.
 7. A metalloceneaccording to claim 1, wherein group Z is an open-pentadienyl containinggroup and it comprises a radical of formula (V):

where: G is a carbon atom, a nitrogen atom, a silicon atom, or aphosphorus atom; L is a CR³R^(3′) radical, a SiR³R^(3′) radical, aNR^(3″) radical, a PR^(3″) radical, an oxygen atom, or a sulfur atom; L′is a CR⁴R^(4′) radical, a Si R⁴R^(4′) radical, a NR^(4″) radical, aPR^(4″) radical, an oxygen atom, or a sulfur atom; R², R³, R^(3′),R^(3″), R⁴, R^(4′), R^(4″), and R⁵, are the same or different from eachother, can be hydrogen, a linear or branched C₁–C₂₀ hydrocarbon radical,a linear or branched, C₁–C₂₀ halocarbon radical, a C₁–C₂₀hydrohalocarbon radical, a C₁–C₂₀ alkoxy radical, a C₃–C₁₂cyclohydrocarbon radical, a C₃–C₁₂ cyclohydrohalocarbon radical, aC₆–C₂₀ aryl radical, a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkylradical, a silicon hydrocarbon radical, a germanium hydrocarbon radical,a phosphorous hydrocarbon radical, a nitrogen hydrocarbon radical, aboron hydrocarbon radical, an aluminum hydrocarbon radical, or a halogenatom; R² and R³, R^(3′) or R^(3″) and/or R⁵ and R⁴, R^(4′) or R^(4″) canform together a 4 to 6 membered ring or a 6 to 20 fused ring system; R³,R^(3′), or R^(3″) and R⁴, R^(4′), or R^(4″) can be joined together sothat the five numbered atomic centers of the six π electron centralradical are part of a 7 to 20 membered ring system.
 8. A metalloceneaccording to claim 1, wherein i is 1, j is 1, and ii is 1, and at leastone β substituent on either Y or Z is a bulky group sterically largerthan hydrogen or a fluorine atom.
 9. A metallocene according to claim 1,wherein i is 1, j is 1, and where both Y and Z are bilaterally orpseudo-bilaterally symmetric and where Y or Z has at least one βsubstituent larger than hydrogen.
 10. A metallocene according to claim1, wherein i is 1, j is 1, and where one or both Y and Z are notbilaterally or pseudo-bilaterally symmetric, Y or Z having at least oneβ substituent larger than hydrogen.
 11. A metallocene according to claim10, having Cs or pseudo-Cs symmetry.
 12. A ligand of formula (II):Y_(j)R″_(i)Z_(jj)  (II) wherein (1) Y is a coordinating group containinga six π electron central radical to which is fused one or more ringscontaining at least one non-carbon atom selected from B, N, O, Al, P, S,Ga, Ge, As, Se, In, Sn, Sb, and Te; (2) R″ is a divalent bridge betweenthe Y and Z groups; (3) Z is a coordinating group having the samemeaning as Y or is an open pentadienyl containing group, acyclopentadienyl containing group, a heterocyclopentadienyl containinggroup, a nitrogen containing group, a phosphorous containing group, anoxygen containing group, or a sulfur containing group; (4) i is 1; (5) jis an integer having a value from 1 to 3; and (6) jj is
 1. 13. Acatalytic system for the polymerization of addition polymerizsablemonomers, comprising the reaction product between: (1) an heterocyclicmetallocene as described in claim 1, and (2) a suitable co-catalystselected from the group consisting of trialkylaluminum,trialkyloxyaluminum, dialkylaluminum halides, alkylaluminum halides, andalumoxane.
 14. A catalytic system according to claim 13, wherein theco-catalyst is an alumoxane.
 15. A process for polymerizing additionpolymerizable monomers, comprising contacting at least one catalyticsystem, as described in claim 13, with at least one additionpolymerizable monomer.
 16. A process according to claim 15, comprisingcontacting the metallocene contained in the catalytic system with asuitable co-catalyst, either prior to or after the metallocene isbrought into contact with the monomer.
 17. A process according to claim15, comprising the following steps: a) contacting the catalytic systemwith a small amount of the addition polymerizable monomer, to form apre-polymerized catalyst; and b) contacting the pre-polymerized catalystobtained in step (a) with the addition polymerizable monomers.
 18. Aprocess according to claim 15, for the production of polyethylene,isotactic, syndiotactic, hemi-isotactic, atactic polypropylene,polyethylene copolymers, or polypropylene copolymers.
 19. A metalloceneaccording to claim 2, wherein Y is represented by the followingformulae:

wherein: (i) the X atoms are the same or different from each other, canbe N, P, NR^(g), PR^(g), 0 or S; when a fused ring has two heteroatoms,then one X can be O or S the other X can be N, P, NR^(g) or PR^(g), orone can be N or P and the other can be NR^(g) or PR^(g), so that themolecular species represents a chemically viable group; (ii) whereinR^(g) a linear or branched C₁–C₂₀ hydrocarbon radical, optionallysubstituted with one or more halogen, hydroxy, alkoxy group, a C₃–C₁₂cyclohydrocarbon radical, a C₃–C₁₂ cyclohydrohalocarbon radical,optionally substituted with one or more halogen, C₆–C₂₀ aryl radical,C₇–C₂₀ alkylaryl radical, C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical or a halogen atom; (iii) the Rgroups, the same or different from each other, can be hydrogen, a linearor branched C₁–C₂₀ hydrocarbon radical, optionally substituted with oneor more halogen, hydroxy, alkoxy, a C₃–C₁₂ cyclohydrohalocarbon radical,optionally substituted with one or more halogen, a C₆–C₂₀ aryl radical,a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical, or a halogen atom, twoadjacent R groups can form together a saturated, unsaturated, oraromatic fused ring; (iv) n and m are integers which have values from 0to the maximum number of substituents that the ring can accommodate; (v)R^(α) and R^(β) representing α and β substituents respectively, are thesame or different from each other, can be hydrogen, a linear or branchedC₁–C₂₀ hydrocarbon radical, optionally substituted with one or morehalogen, hydroxy, or alkoxy, a C₃–C₂₀ cyclohydrocarbon radical,optionally substituted with one or more halogens, a C₆–C₂₀ aryl radical,a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical, or a halogen atom; twoadjacent R^(α) and R^(β) groups can form together a saturated,unsaturated, or aromatic fused ring; and (vi) R^(b) is a hydrogen,halogen, linear or branched, saturated or unsaturated, C₁–C₂₀ alkyl,C₁–C₂₀ alkoxyl, C₆–C₂₀ aryl, C₇–C₂₀ alkylaryl, C₇–C₂₀ arylalkyl, C₁–C₂₀acyloxyl group, optionally containing a silicon atom, or R^(b) is thebridging divalent group R″.
 20. A metallocene of formula (III):Y_(j)R″_(i)Z_(jj)MeQ_(k)  (III) wherein (1) Y is a coordinating groupcontaining a six π electron central radical directly coordinating Me towhich radical is fused one or more rings containing at least onenon-carbon atom selected from B, N, O, Al, P, S, Ga, Ge, As, Se, In, Sn,Sb, and Te; (2) R″ is a divalent bridge between the Y and Z groups; (3)Z is a coordinating group having the same meaning as Y or is an openpentadienyl containing group, a cyclopentadienyl containing group, aheterocyclopentadienyl containing group, a nitrogen containing group, aphosphorous containing group, an oxygen containing group, or a sulfurcontaining group; (4) Me is an element belonging to Group 3, 4, 5, 6, orto the lanthanide or actinide series of the Periodic Table of theElements; (5) Q is a linear or branched, saturated or unsaturated alkylradical, aryl radical, alkylaryl radical, arylalkyl radical, or ahalogen atom; (6) i is an integer having a value of 0 or 1; (7) j is aninteger having a value from 1 to 3; (8) jj is an integer having a valuefrom 0 to 2; and (9) k is an integer having a value from 1 to
 3. 21. Ametallocene according to claim 20, wherein Y contains one heterocyclicring fused to the central six π electron central radical.
 22. Ametallocene according to claim 21, wherein Y is a substitutedcyclopentadienyl group of formula:

wherein the groups R^(a), are identical or different from each other,are selected from the group consisting of hydrogen, linear or branched,saturated or unsaturated, C₁–C₂₀ alkyl, C₃–C₂₀ cycloalkyl, C₆–C₂₀ aryl,C₇–C₂₀ alkylaryl, and C₇–C₂₀ arylalkyl radicals, and wherein at leasttwo adjacent R^(a) groups form a condensed heterocyclic C₅–C₇ ringcontaining at least one non-carbon atom selected from B, N, O, Al, P, S,Ga, Ge, As, Se, In, Sn, Sb, and Te; R^(b) is hydrogen, halogen, linearor branched, saturated or unsaturated, C₁–C₂₀ alkyl, C₁–C₂₀ alkoxyl,C₆–C₂₀-aryl, C₇–C₂₀ alkylaryl, C₇–C₂₀ arylalkyl, C₁–C₂₀ acyloxyl group,optionally containing a silicon atom, or R^(b) is the bridging divalentgroup R″.
 23. A metallocene according to claim 20, wherein Y contains atleast two heteroatoms.
 24. A metallocene according to claim 20, whereini is 1, j is 1, and Z has the same meaning as Y.
 25. A metalloceneaccording to claim 20, wherein i is 1, j is 1, and Z is acycolpentadienyl containing group, an open-pentadienyl containing group,a nitrogen containing group, a phosphorus containing group, an oxygencontaining group, or a sulfur containing group.
 26. A metalloceneaccording to claim 20, wherein group Z is an open-pentadienyl containinggroup and it comprises a radical of formula (V):

where: G is a carbon atom, a nitrogen atom, a silicon atom, or aphosphorus atom; L is a CR³R^(3′) radical, a SiR³R^(3′) radical, aNR^(3″) radical, a PR^(3″) radical, an oxygen atom, or a sulfur atom;L′is a CR⁴R^(4′) radical, a Si R⁴R^(4′) radical, a NR^(4″) radical, aPR^(4″)radical, an oxygen atom, or a sulfur atom; R², R³, R^(3′),R^(3″), R⁴, R^(4′), R^(4″), and R⁵, are the same or different from eachother, can be hydrogen, a linear or branched C₁–C₂₀ hydrocarbon radical,a linear or branched, C₁–C₂₀ halocarbon radical, a C₁–C₂₀hydrohalocarbon radical, a C₁–C₂₀ alkoxy radical, a C₃–C₁₂cyclohydrocarbon radical, a C₃–C₁₂ cyclohydrohalocarbon radical, aC₆–C₂₀ aryl radical, a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkylradical, a silicon hydrocarbon radical, a germanium hydrocarbon radical,a phosphorous hydrocarbon radical, a nitrogen hydrocarbon radical, aboron hydrocarbon radical, an aluminum hydrocarbon radical, or a halogenatom; R² and R³, R^(3′) or R^(3″) and/or R⁵ and R⁴, R^(4′) or R^(4″) canform together a 4 to 6 membered ring or a 6 to 20 fused ring system; R³,R^(3′), or R^(3″) and R⁴, R^(4′), or R^(4″) can be joined together sothat the five numbered atomic centers of the six π electron centralradical are part of a 7 to 20 membered ring system.
 27. A metalloceneaccording to claim 20, wherein i is 1, j is 1, and ii is 1, and at leastone β substituent on either Y or Z is a bulky group sterically largerthan hydrogen or a fluorine atom.
 28. A metallocene according to claim20, wherein i is 1, j is 1, and where both Y and Z are bilaterally orpseudo-bilaterally symmetric and where Y or Z has at least one βsubstituent larger than hydrogen.
 29. A metallocene according to claim20, wherein i is 1, j is 1, and where one or both Y and Z are notbilaterally or pseudo-bilaterally symmetric, Y or Z having at least oneβ substituent larger than hydrogen.
 30. A metallocene according to claim29, having Cs or pseudo-Cs symmetry.
 31. A catalytic system for thepolymerization of addition polymerizable monomers, comprising thereaction product between: (1) an heterocyclic metallocene as describedin claim 20, and (2) a suitable co-catalyst selected from the groupconsisting of trialkylaluminum, trialkyloxyaluminum, dialkylaluminumhalides, alkylaluminum halides, and alumoxane.
 32. A catalytic systemaccording to claim 31, wherein the co-catalyst is an alumoxane.
 33. Aprocess for polymerizing addition polymerizable monomers, comprisingcontacting at least one catalytic system, as described in claim 31, withat least one addition polymerizable monomer.
 34. A process according toclaim 33, comprising contacting the metallocene contained in thecatalytic system with a suitable co-catalyst, either prior to or afterthe metallocene is brought into contact with the monomer.
 35. A processaccording to claim 33, comprising the following steps: a) contacting thecatalytic system with a small amount of the addition polymerizablemonomer, to form a pre-polymerized catalyst; and b) contacting thepre-polymerized catalyst obtained in step (a) with the additionpolymerizable monomers.
 36. A process according to claim 33, for theproduction of polyethylene, isotactic, syndiotactic, hemi-isotactic,atactic polypropylene, polyethylene copolymers, or polypropylenecopolymers.
 37. A metallocene according to claim 21, wherein Y isrepresented by the following formulae:

wherein: (i) the X atoms are the same or different from each other, canbe N, P, NR^(g), PR^(g), 0 or S; when a fused ring has two heteroatoms,then one X can be O or S the other X can be N, P, NR^(g) or PR^(g), orone can be N or P and the other can be NR^(g) or PR^(g), so that themolecular species represents a chemically viable group; (ii) whereinR^(g) a linear or branched C₁–C₂₀ hydrocarbon radical, optionallysubstituted with one or more halogen, hydroxy, alkoxy group, a C₃–C₁₂cyclohydrocarbon radical, a C₃–C₁₂ cyclohydrohalocarbon radical,optionally substituted with one or more halogen, C₆–C₂₀ aryl radical,C₇–C₂₀ alkylaryl radical, C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical or a halogen atom; (iii) the Rgroups, the same or different from each other, can be hydrogen, a linearor branched C₁–C₂₀ hydrocarbon radical, optionally substituted with oneor more halogen, hydroxy, alkoxy, a C₃–C₁₂ cyclohydrohalocarbon radical,optionally substituted with one or more halogen, a C₆–C₂₀ aryl radical,a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical, or a halogen atom, twoadjacent R groups can form together a saturated, unsaturated, oraromatic fused ring; (iv) n and m are integers which have values from 0to the maximum number of substituents that the ring can accommodate; (v)R^(α) and R^(β) representing α and β substituents respectively, are thesame or different from each other, can be hydrogen, a linear or branchedC₁–C₂₀ hydrocarbon radical, optionally substituted with one or morehalogen, hydroxy, or alkoxy, a C₃–C₂₀ cyclohydrocarbon radical,optionally substituted with one or more halogens, a C₆–C₂₀ aryl radical,a C₇–C₂₀ alkylaryl radical, a C₇–C₂₀ arylalkyl radical, a siliconhydrocarbon radical, a germanium hydrocarbon radical, a phosphoroushydrocarbon radical, a nitrogen hydrocarbon radical, a boron hydrocarbonradical, an aluminum hydrocarbon radical, or a halogen atom; twoadjacent R^(α) and R^(β) groups can form together a saturated,unsaturated, or aromatic fused ring; and (vi) R^(b) is a hydrogen,halogen, linear or branched, saturated or unsaturated, C₁–C₂₀ alkyl,C₁–C₂₀ alkoxyl, C₆–C₂₀ aryl, C₇–C₂₀ alkylaryl, C₇–C₂₀ arylalkyl, C₁–C₂₀acyloxyl group, optionally containing a silicon atom, or R^(b) is thebridging divalent group R″.
 38. A ligand according to claim 12, whereinY is represented by the following formulae: